UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13G
                    Under the Securities Exchange Act of 1934

                               (Amendment No. 1)*

                                Siderca S.A.I.C.
--------------------------------------------------------------------------------
                                (Name of Issuer)

                             Class A Ordinary Shares
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    825863103
                      ------------------------------------
                                 (CUSIP Number)

                                December 31, 2002
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

[ ]      Rule 13d-1(b)

[ ]      Rule 13d-1(c)

[X]      Rule 13d-1(d)

*     The remainder of this cover page shall be filled out for a reporting
      person's initial filing on this form with respect to the subject class of
      securities, and for any subsequent amendment containing information which
      would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).





...............................
CUSIP NO. 825863103
...............................

--------------------------------------------------------------------------------
1.    NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      ROBERTO ROCCA

--------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                            (a)  [ ]

                                                            (b)  [ ]

--------------------------------------------------------------------------------
3.    SEC USE ONLY

--------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      ITALY

--------------------------------------------------------------------------------
                     5. SOLE VOTING POWER: NONE

  NUMBER OF          ...........................................................
   SHARES            6. SHARED VOTING POWER: 991,085,542
BENEFICIALLY
  OWNED BY           ...........................................................
    EACH             7. SOLE DISPOSITIVE POWER: NONE
 REPORTING
   PERSON            ...........................................................
    WITH:            8. SHARED DISPOSITIVE POWER: 991,085,542

--------------------------------------------------------------------------------
9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 991,085,542

--------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
      INSTRUCTIONS)

                                                                 [ ]
--------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9): 99.11%

--------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): IN

--------------------------------------------------------------------------------


                               Page 2 of 28 Pages



...............................
CUSIP NO. 825863103
...............................

--------------------------------------------------------------------------------
1.    NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      ROCCA & PARTNERS S.A.

--------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                            (a)  [ ]

                                                            (b)  [ ]

--------------------------------------------------------------------------------
3.    SEC USE ONLY

--------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      BRITISH VIRGIN ISLANDS

--------------------------------------------------------------------------------
                     5. SOLE VOTING POWER: NONE

  NUMBER OF          ...........................................................
   SHARES            6. SHARED VOTING POWER: 991,085,542
BENEFICIALLY
  OWNED BY           ...........................................................
    EACH             7. SOLE DISPOSITIVE POWER: NONE
 REPORTING
   PERSON            ...........................................................
    WITH:            8. SHARED DISPOSITIVE POWER: 991,085,542

--------------------------------------------------------------------------------
9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 991,085,542

--------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
      INSTRUCTIONS)

                                                                 [ ]
--------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9): 99.11%

--------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): CO

--------------------------------------------------------------------------------


                               Page 3 of 28 Pages





...............................
CUSIP NO. 825863103
...............................

--------------------------------------------------------------------------------
1.    NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      SAN FAUSTIN N.V.

--------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                            (a) [ ]

                                                            (b) [ ]

--------------------------------------------------------------------------------
3.    SEC USE ONLY

--------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      NETHERLANDS ANTILLES

--------------------------------------------------------------------------------
                     5. SOLE VOTING POWER: NONE

  NUMBER OF          ...........................................................
   SHARES            6. SHARED VOTING POWER: 991,085,542
BENEFICIALLY
  OWNED BY           ...........................................................
    EACH             7. SOLE DISPOSITIVE POWER: NONE
 REPORTING
   PERSON            ...........................................................
    WITH:            8. SHARED DISPOSITIVE POWER: 991,085,542

--------------------------------------------------------------------------------
9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 991,085,542

--------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
      INSTRUCTIONS)

                                                                 [ ]

--------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9): 99.11%

--------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): CO

--------------------------------------------------------------------------------


                               Page 4 of 28 Pages



...............................
CUSIP NO. 825863103
...............................

--------------------------------------------------------------------------------
1.    NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      I.I.I. INDUSTRIAL INVESTMENTS INC.

--------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                            (a) [ ]

                                                            (b) [ ]

--------------------------------------------------------------------------------
3.    SEC USE ONLY

--------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      BRITISH VIRGIN ISLANDSS

--------------------------------------------------------------------------------
                     5. SOLE VOTING POWER: NONE

  NUMBER OF          ...........................................................
   SHARES            6. SHARED VOTING POWER: 991,085,542
BENEFICIALLY
  OWNED BY           ...........................................................
    EACH             7. SOLE DISPOSITIVE POWER: NONE
 REPORTING
   PERSON            ...........................................................
    WITH:            8. SHARED DISPOSITIVE POWER: 991,085,542

--------------------------------------------------------------------------------
9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 991,085,542

--------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
      INSTRUCTIONS)

                                                                 [ ]

--------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9): 99.11%

--------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): CO

--------------------------------------------------------------------------------


                               Page 5 of 28 Pages





...............................
CUSIP NO. 825863103
...............................

--------------------------------------------------------------------------------
1.    NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      SIDERTUBES S.A.

--------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                            (a) [ ]

                                                            (b) [ ]

--------------------------------------------------------------------------------
3.    SEC USE ONLY

--------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      LUXEMBOURG

--------------------------------------------------------------------------------
                     5. SOLE VOTING POWER: NONE

  NUMBER OF          ...........................................................
   SHARES            6. SHARED VOTING POWER: 991,085,542
BENEFICIALLY
  OWNED BY           ...........................................................
    EACH             7. SOLE DISPOSITIVE POWER: NONE
 REPORTING
   PERSON            ...........................................................
    WITH:            8. SHARED DISPOSITIVE POWER: 991,085,542

--------------------------------------------------------------------------------
9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 991,085,542

--------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
      INSTRUCTIONS)

                                                                 [ ]

--------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9): 99.11%

--------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): CO

--------------------------------------------------------------------------------


                               Page 6 of 28 Pages





...............................
CUSIP NO. 825863103
...............................

--------------------------------------------------------------------------------
1.    NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      TENARIS S.A.

--------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                            (a) [ ]

                                                            (b) [ ]

--------------------------------------------------------------------------------
3.    SEC USE ONLY

--------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      LUXEMBOURG

--------------------------------------------------------------------------------
                     5. SOLE VOTING POWER: NONE

  NUMBER OF          ...........................................................
   SHARES            6. SHARED VOTING POWER: 991,085,542
BENEFICIALLY
  OWNED BY           ...........................................................
    EACH             7. SOLE DISPOSITIVE POWER: NONE
 REPORTING
   PERSON            ...........................................................
    WITH:            8. SHARED DISPOSITIVE POWER: 991,085,542

--------------------------------------------------------------------------------
9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 991,085,542

--------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
      INSTRUCTIONS)

                                                                 [ ]

--------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9): 99.11%

--------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): CO

--------------------------------------------------------------------------------


                               Page 7 of 28 Pages





...............................
CUSIP NO. 825863103
...............................

--------------------------------------------------------------------------------
1.    NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      INVERTUB S.A.

--------------------------------------------------------------------------------
2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                            (a) [ ]

                                                            (b) [ ]

--------------------------------------------------------------------------------
3.    SEC USE ONLY

--------------------------------------------------------------------------------
4.    CITIZENSHIP OR PLACE OF ORGANIZATION

      ARGENTINA

--------------------------------------------------------------------------------
                     5. SOLE VOTING POWER: NONE

  NUMBER OF          ...........................................................
   SHARES            6. SHARED VOTING POWER: 991,085,542
BENEFICIALLY
  OWNED BY           ...........................................................
    EACH             7. SOLE DISPOSITIVE POWER: NONE
 REPORTING
   PERSON            ...........................................................
    WITH:            8. SHARED DISPOSITIVE POWER: 991,085,542

--------------------------------------------------------------------------------
9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 991,085,542

--------------------------------------------------------------------------------
10.   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
      INSTRUCTIONS)

                                                                 [ ]

--------------------------------------------------------------------------------
11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9): 99.11%

--------------------------------------------------------------------------------
12.   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): CO

--------------------------------------------------------------------------------


                               Page 8 of 28 Pages



Item 1.
      (a) Name of Issuer:

          Siderca Sociedad Anonima Industrial y Comercial (Siderca S.A.I.C.)

      (b) Address of Issuer's Principal Executive Offices:

          Av. Leandro N. Alem, 1067, Buenos Aires, Argentina

Item 2.
      (a) Name of Person Filing:

          Roberto Rocca
          Rocca & Partners S.A.
          San Faustin N.V.
          I.I.I. Industrial Investments Inc.
          Sidertubes S.A.
          Tenaris S.A.
          Invertub S.A.

      (b) Address of Principal Business Office or, if none, Residence:

           Roberto Rocca
           Av. Leandro N. Alem 1067, 29th floor
           Buenos Aires
           Argentina

           Rocca & Partners
           Vanterpool Plaza, 2nd Floor,
           Wickhams Cay I, Road Town, Tortola
           British Virgin Islands

           San Faustin N.V.
           Berg Arrarat 1
           Curacao
           Netherlands Antilles

           I.I.I. Industrial Investments Inc.
           Vanterpool Plaza, 2nd Floor,
           Wickhams Cay I, Road Town
           British Virgin Islands

           Sidertubes S.A.
           23 Avenue Monterey
           L-2086 Luxembourg

           Tenaris S.A.
           23, Avenue Monterey
           L-2163 Luxembourg

           Invertub S.A.
           Av. Leandro N. Alem 1067, 28th Floor,
           Buenos Aires
           Argentina


                               Page 9 of 28 Pages



      (c) Citizenship:

          See item 4 on page 2
          See item 4 on page 3
          See item 4 on page 4
          See item 4 on page 5
          See item 4 on page 6
          See item 4 on page 7
          See item 4 on page 8

      (d) Title of Class of Securities:

          Class A Ordinary Shares

      (e) CUSIP Number:

          825863103

Item 3.     If this statement is filed pursuant toss.ss.240.13d-1(b) or
            240.13d-2(b) or (c), check whether the person filing is a: (Not
            Applicable)

(a) [ ] Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c) [ ] Insurance company as defined in section 3(a)(19) of the Act
        (15 U.S.C. 78c);
(d) [ ] Investment company registered under section 8 of the Investment Company
        Act of 1940 (15 U.S.C. 80a-8);
(e) [ ] An investment adviser in accordance with ss.240.13d-1(b)(1)(ii)(E);
(f) [ ] An employee benefit plan or endowment fund in accordance with
        ss.240.13d-1(b)(1)(ii)(F);
(g) [ ] A parent holding company or control person in accordance with
        ss.240.13d-1(b)(1)(ii)(G);
(h) [ ] A savings association as defined in Section 3(b) of the Federal Deposit
        Insurance Act (12 U.S.C. 1813);
(i) [ ] A church plan that is excluded from the definition of an investment
        company under section 3(c)(14) of the Investment Company Act of 1940
        (15 U.S.C. 80a-3);
(j) [ ] Group, in accordance withss.240.13d-1(b)(1)(ii)(J).

Item 4.     Ownership.

      Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.

      (a) Amount beneficially owned:

          See item 9 on page 2
          See item 9 on page 3
          See item 9 on page 4
          See item 9 on page 5
          See item 9 on page 6
          See item 9 on page 7
          See item 9 on page 8


                              Page 10 of 24 pages



      (b) Percent of class:

          See item 11 on page 2
          See item 11 on page 3
          See item 11 on page 4
          See item 11 on page 5
          See item 11 on page 6
          See item 11 on page 7
          See item 11 on page 8

      (c) Number of shares as to which the person has:

   (i) Sole power to vote or to direct the vote:

          See item 5 on page 2
          See item 5 on page 3
          See item 5 on page 4
          See item 5 on page 5
          See item 5 on page 6
          See item 5 on page 7
          See item 5 on page 8

   (ii) Shared power to vote or to direct the vote:

          See item 6 on page 2
          See item 6 on page 3
          See item 6 on page 4
          See item 6 on page 5
          See item 6 on page 6
          See item 6 on page 7
          See item 6 on page 8

   (iii) Sole power to dispose or to direct the disposition of:

          See item 7 on page 2
          See item 7 on page 3
          See item 7 on page 4
          See item 7 on page 5
          See item 7 on page 6
          See item 7 on page 7
          See item 7 on page 8

   (iv) Shared power to dispose or to direct the disposition of:

          See item 8 on page 2
          See item 8 on page 3
          See item 8 on page 4
          See item 8 on page 5
          See item 8 on page 6
          See item 8 on page 7
          See item 8 on page 8


                              Page 11 of 24 pages



Item 5.     Ownership of Five Percent or Less of a Class.

If this statement is being filed to report the fact that as of the date hereof
the reporting person has ceased to be the beneficial owner of more than five
percent of the class of securities, check the following [ ].

      Not applicable.

Item 6.     Ownership of More than Five Percent on Behalf of Another Person.

      Not applicable.

Item 7.     Identification and Classification of the Subsidiary Which Acquired
            the Security Being Reported on By the Parent Holding Company.

      See Exhibit A.

Item 8.     Identification and Classification of Members of the Group.

      Not applicable.

Item 9.     Notice of Dissolution of Group.

      Not applicable.

Item 10.    Certification.

      Not applicable.


                              Page 12 of 24 pages



                                    SIGNATURE

      After  reasonable  inquiry and to the best of my knowledge and belief,  I,
Fernando  Mantilla,  attorney  duly  authorized  by  Roberto  Rocca to sign this
statement,  certify that the information set forth in this Schedule 13G is true,
complete and correct.

      Pursuant to Rule 13d-1(k)(1),  the undersigned joins in the filing of this
Schedule  13G on his own behalf and on behalf of ROCCA &  PARTNERS,  SAN FAUSTIN
N.V.,  SIDERTUBES S.A., I.I.I.  INDUSTRIAL  INVESTMENTS  INC.,  TENARIS S.A. and
INVERTUB S.A.

January 23, 2003

                                                     ---------------------------
                                                          Fernando Mantilla
                                                          Attorney-in-fact


                              Page 13 of 24 pages



                                    SIGNATURE

      After  reasonable  inquiry and to the best of my knowledge and belief,  I,
Fernando  Mantilla,  attorney  duly  authorized by ROCCA & PARTNERS S.A. to sign
this  statement,  certify that the information set forth in this Schedule 13G is
true, complete and correct.

      Pursuant to Rule 13d-1(k)(1),  the undersigned joins in the filing of this
Schedule 13G on his own behalf and on behalf of Roberto ROCCA, SAN FAUSTIN N.V.,
SIDERTUBES S.A, I.I.I.  INDUSTRIAL  INVESTMENTS INC.,  TENARIS S.A. and INVERTUB
S.A.

January 23, 2003

                                                     ---------------------------
                                                         Fernando Mantilla
                                                         Attorney-in-fact


                              Page 13 of 24 pages



                                    SIGNATURE

      After  reasonable  inquiry and to the best of my knowledge and belief,  I,
Fernando  Mantilla,  attorney  duly  authorized by San Faustin N.V. to sign this
statement,  certify that the information set forth in this Schedule 13G is true,
complete and correct.

      Pursuant  to Rule 13d - 1(k)(1),  the  undersigned  joins in the filing of
this  Schedule  13G on his own behalf and on behalf of  Roberto  Rocca,  ROCCA &
PARTNERS,  SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS INC., TENARIS S.A. and
INVERTUB S.A.

January 23, 2003

                                                     ---------------------------
                                                         Fernando Mantilla
                                                         Attorney-in-fact


                              Page 15 of 24 pages



                                    SIGNATURE

      After  reasonable  inquiry and to the best of my knowledge and belief,  I,
Fernando  Mantilla,  attorney duly authorized by I.I.I.  Industrial  Investments
Inc. to sign this  statement,  certify  that the  information  set forth in this
Schedule 13G is true, complete and correct.

      Pursuant  to Rule 13d - 1(k)(1),  the  undersigned  joins in the filing of
this  Schedule  13G on his own behalf and on behalf of  Roberto  Rocca,  ROCCA &
PARTNERS, SAN FAUSTIN N.V., SIDERTUBES S.A., TENARIS S.A. and INVERTUB S.A.

January 23, 2003

                                                     ---------------------------
                                                         Fernando Mantilla
                                                         Attorney-in-fact


                              Page 16 of 24 pages



                                    SIGNATURE

      After  reasonable  inquiry and to the best of my knowledge and belief,  I,
Fernando  Mantilla,  attorney duly  authorized  by Sidertubes  S.A. to sign this
statement,  certify that the information set forth in this Schedule 13G is true,
complete and correct.

      Pursuant to Rule 13d -1(k)(1), the undersigned joins in the filing of this
Schedule 13G on his own behalf and on behalf of Roberto Rocca, ROCCA & PARTNERS,
I.I.I.  INDUSTRIAL INVESTMENTS INC., SAN FAUSTIN N.V., TENARIS S.A. and INVERTUB
S.A.

January 23, 2003

                                                     ---------------------------
                                                          Fernando Mantilla
                                                          Attorney-in-fact


                              Page 17 of 24 pages



                                    SIGNATURE

      After  reasonable  inquiry and to the best of my knowledge and belief,  I,
Fernando  Mantilla,  attorney  duly  authorized  by  Tenaris  S.A.  to sign this
statement,  certify that the information set forth in this Schedule 13G is true,
complete and correct.

      Pursuant to Rule 13d -1(k)(1), the undersigned joins in the filing of this
Schedule 13G on his own behalf and on behalf of Roberto Rocca, ROCCA & PARTNERS,
I.I.I.  INDUSTRIAL  INVESTMENTS  INC.,  SAN FAUSTIN  N.V.,  SIDERTUBES  S.A. and
INVERTUB S.A.

January 23, 2003

                                                     ---------------------------
                                                          Fernando Mantilla
                                                          Attorney-in-fact


                              Page 18 of 24 pages



                                    SIGNATURE

      After  reasonable  inquiry and to the best of my knowledge and belief,  I,
Fernando  Mantilla,  attorney  duly  authorized  by  Invertub  S.A. to sign this
statement,  certify that the information set forth in this Schedule 13G is true,
complete and correct.

      Pursuant  to Rule 13d - 1(k)(1),  the  undersigned  joins in the filing of
this  Schedule  13G on his own behalf and on behalf of  Roberto  Rocca,  ROCCA &
PARTNERS,  I.I.I. INDUSTRIAL INVESTMENTS INC., SAN FAUSTIN N.V., SIDERTUBES S.A.
and TENARIS S.A.

January 23, 2003

                                                     ---------------------------
                                                          Fernando Mantilla
                                                          Attorney-in-fact


                              Page 19 of 24 pages




                                  EXHIBIT INDEX

Exhibit     Description

A           Item 7 Information.
B           Power of Attorney for Roberto Rocca, dated March 7, 2002*.
C           Power of Attorney for Rocca & Partners S.A., dated March 7, 2002*.
D           Power of Attorney for San Faustin N.V., dated March 7, 2002*.
E           Power of Attorney for I.I.I. Industrial Investments Inc., dated
              January 17, 2003.
F           Power of Attorney for Sidertubes S.A., dated March 7, 2002*.
G           Power of Attorney for Tenaris S.A., dated January 17, 2003
H           Power of Attorney for Invertub S.A., dated January 17, 2003

----------
*     Incorporated by reference to the power of attorney filed as exhibit to the
      Schedule 13G filed by the reporting persons on March 8, 2002.


                              Page 20 of 24 pages



                                                                       EXHIBIT A

                               ITEM 7 INFORMATION

Roberto  Rocca  controls a majority of the voting power of Rocca & Partners S.A.
Roberto Rocca and Rocca & Partners share majority  voting power over San Faustin
N.V.

Sidertubes S.A. is a wholly-owned  subsidiary of I.I.I.  Industrial  Investments
Inc., which is a wholly-owned subsidiary of San Faustin N.V.

Tenaris S.A., a subsidiary of  Sidertubes  S.A. and San Faustin N.V.,  holds the
shares of Siderca S.A.I.C. directly and through its subsidiary, Invertub S.A.


                              Page 21 of 24 pages



                                                                       EXHIBIT E

               [LETTERHEAD OF I.I.I. INDUSTRIAL INVESTMENTS Inc.]

                                POWER OF ATTORNEY

      The  undersigned,   Roberto  Bonatti,   President  of  I.I.I.   INDUSTRIAL
INVESTMENTS  Inc.,  a company  organized  under the laws of the  British  Virgin
Islands,  hereby  constitutes  and appoints  Carlos Manuel  Franck,  Fernando R.
Mantilla and Carlos E.  Zandona,  and each of them,  as attorneys or attorney of
the undersigned with full power of substitution and  resubstitution,  to sign on
its behalf a Statement  on Schedule  13G relating to the Common Stock of SIDERCA
S.A.I.C., including any agreements attached as exhibits thereto, and to sign any
or all  amendments to such  Statement,  and to file the same,  with all exhibits
thereto,  and other documents in connection  therewith,  with the Securities and
Exchange Commission, granting unto said attorneys or attorney, and each of them,
full  power  and  authority  to do and  perform  each and  every  act and  thing
requisite and necessary to be done in and about the premises,  hereby  ratifying
and  confirming  all that said  attorneys or  attorney,  or any of them or their
substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

By: /s/ Roberto Bonatti
    -------------------
    Roberto Bonatti
    President

Dated: January 17, 2003


                              Page 22 of 24 pages



                                                                       EXHIBIT G

                             [LETTERHEAD OF TENARIS]

                                POWER OF ATTORNEY

      The undersigned,  Fernando  Mantilla,  Director of Tenaris S.A., a company
organized  under the laws of the  Luxembourg,  hereby  constitutes  and appoints
Carlos Manuel  Franck,  Fernando R. Mantilla and Carlos E. Zandona,  and each of
them,  as  attorneys  or  attorney  of  the  undersigned   with  full  power  of
substitution and  resubstitution,  to sign on its behalf a Statement on Schedule
13G relating to the Common Stock of SIDERCA  S.A.I.C.,  including any agreements
attached  as  exhibits  thereto,  and to  sign  any or all  amendments  to  such
Statement,  and to file the same, with all exhibits thereto, and other documents
in connection therewith,  with the Securities and Exchange Commission,  granting
unto said attorneys or attorney,  and each of them,  full power and authority to
do and perform each and every act and thing  requisite  and necessary to be done
in and  about  the  premises,  hereby  ratifying  and  confirming  all that said
attorneys or attorney,  or any of them or their  substitute or substitutes,  may
lawfully do or cause to be done by virtue hereof.





By: /s/ Fernando Mantilla
    ---------------------
    Fernando Mantilla
    Director

Dated: January 17, 2003


                              Page 23 of 24 pages



                                                                       EXHIBIT H

                          [LETTERHEAD OF INVERTUB S.A.]

                                POWER OF ATTORNEY

      The  undersigned,  Carlos  Franck,  President of INVERTUB  S.A., a company
organized  under the laws of the  Argentina  Republic,  hereby  constitutes  and
appoints Carlos Manuel Franck,  Fernando R. Mantilla and Carlos E. Zandona,  and
each of them,  as  attorneys or attorney of the  undersigned  with full power of
substitution and  resubstitution,  to sign on its behalf a Statement on Schedule
13G relating to the Common Stock of SIDERCA  S.A.I.C.,  including any agreements
attached  as  exhibits  thereto,  and to  sign  any or all  amendments  to  such
Statement,  and to file the same, with all exhibits thereto, and other documents
in connection therewith,  with the Securities and Exchange Commission,  granting
unto said attorneys or attorney,  and each of them,  full power and authority to
do and perform each and every act and thing  requisite  and necessary to be done
in and  about  the  premises,  hereby  ratifying  and  confirming  all that said
attorneys or attorney,  or any of them or their  substitute or substitutes,  may
lawfully do or cause to be done by virtue hereof.

By: /s/ Carlos Franck
    -----------------
    Carlos Franck
    President

Dated: January 17, 2003


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