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                                                                     EXHIBIT 3.1


                            CERTIFICATE OF AMENDMENT
                                     TO THE
                            ARTICLES OF INCORPORATION


The undersigned, Michael F. Curran and Dennis G. Berryhill, President and
Secretary, respectively, of WILLBROS GROUP, INC., a corporation duly organized
and existing under and by virtue of the laws of the Republic of Panama, do
hereby amend the Restated Articles of Incorporation, as amended, of WILLBROS
GROUP, INC. as follows:

1.     By substituting and replacing ARTICLE THIRD so that henceforth said
       ARTICLE THIRD of said Articles shall read in its entirety as follows:

              "THIRD: Capital. The authorized capital of the Corporation shall
              consist of ONE MILLION SEVEN HUNDRED SIXTY THOUSAND U.S. DOLLARS
              (U.S. $1,760,000), consisting of: THIRTY-FIVE MILLION (35,000,000)
              shares of common stock, par value FIVE U.S. CENTS (U.S. $.05) per
              share ("Common Stock"); and ONE MILLION (1,000,000) shares of
              class A preferred stock, par value ONE U.S. CENT (U.S. $.01) per
              share ("Class A Preferred Stock"). Shares shall all be in
              nominative form and may not be issued to bearer.

              A.     (a) Voting. Each share of Common Stock shall entitle the
              registered holder thereof to one vote on all matters brought
              before the stockholders of the Corporation for a vote.

                     (b) Restrictions on Transfer to Preserve Tax Status. It is
              in the best interests of the Corporation and its stockholders that
              the Corporation's status as a non-controlled foreign corporation
              ("Non-CFC") under the United States Internal Revenue Code of 1986,
              as amended from time to time (the "Code"), be preserved.
              Therefore, any purported Transfer (as hereinafter defined) of any
              shares of Common Stock to any person or entity, which would result
              in such person or entity, together with any other person or entity
              whose shares of Common Stock would be aggregated with such person
              or entity for purposes of Section 957 of the Code, being the
              beneficial owner of ten percent (10%) or more of the issued and
              outstanding shares of Common Stock, will be subject to a
              determination by the Board of Directors in good faith, in its sole
              discretion, that such Transfer would not in any way, directly or
              indirectly, affect the Corporation's Non-CFC status. The
              transferee or transferor proposed to be involved in such Transfer
              shall give to the Secretary of the Corporation not less than
              thirty (30) days prior written notice of such proposed Transfer.
              In the event of an attempted Transfer in violation of this
              paragraph (b), the purported transferee shall acquire no rights
              whatsoever in such shares of Common Stock. If the Board of
              Directors shall at any time determine in good faith that a
              Transfer has taken place in violation of this paragraph (b) or
              that a person intends to acquire, has attempted to acquire or may
              acquire ownership of any shares of Common Stock in violation of
              this paragraph (b), the Board of



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              Directors shall take such action as it deems advisable to refuse
              to give effect to or to prevent such Transfer, including without
              limitation instituting proceedings to enjoin such Transfer. In the
              case of an ambiguity in the application of any of the provisions
              of this paragraph (b), the Board of Directors shall have the power
              to determine the application of the provisions of this paragraph
              (b) with respect to any situation based on the facts known to it.
              For purposes of this paragraph (b), the term "Transfer" shall mean
              any sale, transfer, gift, assignment, devise or other disposition
              of Common Stock, including without limitation (1) the granting of
              any option or entering into of any agreement for the sale,
              transfer or other disposition of Common Stock, or (2) the sale,
              transfer, assignment or other disposition of any securities or
              rights convertible into or exchangeable for Common Stock, whether
              voluntary or involuntary, whether of record or beneficially, and
              whether by operation of law or otherwise. Nothing in this
              paragraph (b) precludes the settlement of any transaction entered
              into through the facilities of the New York Stock Exchange.

              B. Class A Preferred Stock may be issued from time to time in one
              or more series, each of such series to have such voting powers,
              full or limited, or no voting powers, and such designations,
              preferences and relative, participating, optional or other special
              rights, and qualifications, limitations or restrictions thereon or
              thereof, as are stated and expressed herein and in the resolution
              or resolutions providing for the issue of such series adopted by
              the Board of Directors as hereinafter provided. Authority is
              hereby expressly granted to the Board of Directors, subject to the
              provisions of this Part B, to authorize the issue of one or more
              series of Class A Preferred Stock and, with respect to each
              series, to fix by resolution or resolutions providing for the
              issue of such series:

                     (a) The number of shares to constitute such series and the
              distinctive designation thereof, provided that unless otherwise
              stated in any resolution or resolutions relating to such series,
              such number of shares may be increased or decreased by the Board
              of Directors in connection with any classification or
              reclassification of unissued shares of Class A Preferred Stock;

                     (b) The annual dividend rate on the shares of such series
              and the date or dates from which dividends shall accumulate;

                     (c) Whether the holders of such series are or are not
              entitled to participate in earnings of the Corporation through
              dividends in excess of (or in lieu of) dividends at an annual rate
              and the terms of any such right to participate;

                     (d) Whether or not the shares of such series shall be
              subject to redemption, the limitations and restrictions with
              respect to such redemption, if any, and the times of redemption of
              the shares of such series and the amounts (or methods of
              calculating such amounts) which the holders of such series shall
              be entitled to receive upon the redemption thereof, which amounts
              (or method of calculating such amounts) may vary at different
              redemption dates and may also, with respect to shares redeemed
              through the operation of any retirement or sinking fund, be
              different from the amounts (or method of calculating such amounts)
              with respect to shares otherwise redeemed;



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                     (e) The amount (or method of calculating such amount) which
              the holders of such series shall be entitled to receive upon the
              voluntary or involuntary liquidation, dissolution or winding up of
              the Corporation;

                     (f) Whether or not the shares of such series shall be
              subject to the operation of a retirement or sinking fund and, if
              so, the extent to and manner in which it shall be applied to the
              purchase or redemption of the shares of such series for retirement
              or to other corporate purposes and the terms and provisions
              relative to the operation thereof;

                     (g) Whether or not the shares of such series shall be
              convertible into, or exchangeable for, shares of stock of any
              other class or classes, or of any other series of the same class,
              and if so convertible or exchangeable, the price or prices or the
              rate or rates of conversion or exchange and the method, if any, of
              adjusting the same, and the other terms and conditions of such
              conversion or exchange;

                     (h) The voting rights, if any, of holders of shares of such
              series in addition to the voting rights provided for by applicable
              law;

                     (i) The limitations and restrictions, if any, to be
              effective while any shares of such series are outstanding upon the
              payment of dividends or making of other distributions on, and upon
              the purchase, redemption or other acquisition by the Corporation
              of Common Stock or any other class or classes of stock of the
              Corporation ranking junior to the shares of such series;

                     (j) The conditions or restrictions, if any, upon the
              creation of indebtedness of the Corporation or upon the issue of
              any additional stock (including additional shares of such series
              or of any other series or class) ranking on a parity with or prior
              to the shares of such series as to dividends or upon liquidation;
              and

                     (k) Any other preference and relative, participating,
              optional, or other special rights, and qualifications, limitations
              or restrictions thereon or thereof, as shall not be inconsistent
              with this Part B.

                     All shares of any one series of Class A Preferred Stock
              shall be identical with each other in all respects, except that
              shares of any one series issued at different times may differ as
              to the dates from which dividends thereon shall be cumulative if
              dividends on such series accumulate; and all series shall rank
              equally and be identical in all respects, except as permitted by
              the foregoing provisions of this Part B.

                     For purpose hereof and of any resolution of the Board of
              Directors providing for the classification or reclassification of
              any shares of Class A Preferred Stock or for the purpose of any
              certificate filed with the Republic of Panama (unless otherwise
              provided in any such resolution or certificate):

                            (i) The term "outstanding," when used in reference
                     to shares of stock, shall mean issued shares, excluding
                     shares held by the Corporation and shares called for
                     redemption, funds for the redemption of which shall have
                     been deposited in trust; and

                            (ii) The amount of dividends "accrued" on any share
                     of Class A Preferred Stock of any series providing for
                     cumulative dividends as at any dividend date shall be
                     deemed to be the amount of any unpaid dividends accumulated
                     thereon to and including such dividend date, whether or not
                     earned or declared, and the amount of dividends



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                     "accrued" on any share of Class A Preferred Stock of any
                     series as at any date other than a dividend date shall be
                     calculated thereon to and including the last preceding
                     dividend date, whether or not earned or declared, plus an
                     amount equivalent to the pro rata portion of the periodic
                     dividend with respect thereto at the annual dividend rate
                     fixed for the shares of such series for the period after
                     such last preceding dividend date to and including the date
                     as of which the calculation is made."

         2.   By substituting and replacing ARTICLE EIGHTH so that henceforth
              said ARTICLE EIGHTH of said Articles shall read in its entirety as
              follows:

                     "EIGHTH: Meetings. All the meetings of the stockholders and
                     of the Board of Directors shall be held at the office of
                     the Corporation in the Republic of Panama or at any other
                     place or places, within or without the Republic of Panama,
                     as may be determined from time to time by the Board of
                     Directors.

                            In order that the Corporation may determine the
                     stockholders entitled to notice of or to vote at any
                     meeting of stockholders or any adjournment thereof, or for
                     the purpose of any other lawful action, the Board of
                     Directors may fix in advance a record date, which record
                     date shall not be more than sixty (60) nor less than ten
                     (10) days before the date of such meeting. A determination
                     of stockholders of record entitled to notice of or to vote
                     at a meeting of stockholders shall apply to any adjournment
                     of the meeting; provided, however, that the Board of
                     Directors may fix a new record date for the adjourned
                     meeting."

       Signed in Panama City, Panama, on the 30th day of May, 2002.


                                       WILLBROS GROUP, INC.


                                       By:      /s/ Michael F. Curran
                                          --------------------------------------
                                            Michael F. Curran
                                            President


                                       By:      /s/ Dennis G. Berryhill
                                          --------------------------------------
                                            Dennis G. Berryhill
                                            Secretary

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