AMENDMENT NO. 2
                                       TO
                          GST TELECOMMUNICATIONS, INC.
                         COMMON STOCK PURCHASE AGREEMENT



                  THIS AMENDMENT NO. 2 TO GREENSTAR TELECOMMUNICATIONS INC.
COMMON STOCK PURCHASE AGREEMENT (this "Amendment") is entered into as of May 24,
1996, by and among GST Telecommunications, Inc., a Canadian corporation formerly
known as "Greenstar Telecommunications Inc." (the "Company"), Tomen America
Inc., a New York corporation ("Tomen America"), and Tomen Corporation, a
Japanese corporation ("Tomen Corp.").

                  A. The Company, Tomen Corp., and Tomen America are party to
the Greenstar Telecommunications Inc. Common Stock Purchase Agreement, dated
October 24, 1994, as amended by Amendment No. 1, dated as of October 24, 1994,
(the "Purchase Agreement"), whereby Tomen America and Tomen Corp. agreed to
purchase, and the Company agreed to sell, certain Equity Securities of the
Company.

                  B. The Company, Tomen America and Tomen Corp. wish to amend
the Purchase Agreement, to reflect certain additional rights of Tomen America
and Tomen Corp. to purchase Equity Securities of the Company.


                  THE PARTIES HERETO AGREE AS FOLLOWS:

                  1. Definitions. Unless otherwise indicated in this Amendment,
each term set forth in the Purchase Agreement, when used in this Amendment,
shall have the respective meaning given to that term in the Purchase Agreement
and the Schedules and Exhibits thereto.

                  2. New Section 2.3 of the Purchase Agreement is hereby added
to read in its entirety as follows:

                           2.3 Rights Related to Development Company Fundings.
With respect to each Network Project in which Tomen or an Affiliate elects to
participate, Tomen, or an Affiliate shall have the following additional rights
to purchase GSI Equity Securities.

                                    (a) Tomen or an Affiliate shall have the
right (but not the obligation), at the time of the initial funding of the
initial Project Loans for the Network


SF3-92074.2

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Projects in Albuquerque, New Mexico and Tucson, Arizona, to purchase, for a
total purchase price of $800,000.00: (i) the number of shares of GSI Common
Stock, no par value ("GSI Common Stock") equal to the quotient of the purchase
price referred to in the preceding clause divided by the average of the per
share closing price for the GSI Common stock quoted on the AMEX as published in
the Western edition of the Wall Street Journal for the thirty (30) market
trading days preceding the date of the Credit Agreement between GST New Mexico
Lightwave, Inc. and GST Tucson Lightwave, Inc., respectively, as borrower and
Tomen or an Affiliate, as lender, and (ii) 46,155 warrants exercisable for one
share of GSI Common Stock.

                                    (b) Tomen or an Affiliate shall have the
right (but not the obligation), at the time of the initial funding of each
Project Loan made after the Project Loans for the Albuquerque, New Mexico and
Tucson, Arizona Project Loans, to purchase for a total purchase price equal to
10% of the total equity contribution to the Development Company by its
shareholder(s): (i) the number of shares of GSI Common Stock equal to the
quotient of the purchase price referred to in the preceding clause divided by
the average of the per share closing price for the GSI Common stock quoted on
the AMEX as published in the Western edition of the Wall Street Journal for the
thirty (30) market trading days preceding the date of the Credit Agreement
between such Development Company as borrower and Tomen or an Affiliate as
lender, and (ii) with respect to the Network Project to be funded in Hawaii,
75,000 warrants, each exercisable for one share of GSI Common Stock, and with
respect to other Network Projects, a number of such warrants as shall be
mutually agreed by Tomen and GSI.

                                    (c) The representations and warranties of
Tomen set forth in Article 4 of this Purchase Agreement apply to the GSI Common
Stock and warrants issuable pursuant to this Section 2.3.

                  3. The parties hereby affirm that the Purchase Agreement, as
amended hereby, and the other Related Documents, constitute the entire agreement
among any of the parties hereto pertaining to the subject matter thereof and the
amended Purchase Agreement supersedes all prior agreements and understandings
pertaining thereto which are set forth therein. The Purchase Agreement, as
amended hereby, remains in full force and effect.

                  4. This Amendment may be executed in one or more counterparts,
and by the different parties hereto in separate counterparts, each of which when
executed shall be deemed to be an original but all of which taken together shall
constitute one and the same agreement.




                                        2

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                  IN WITNESS WHEREOF, the parties have executed this Agreement
as of the date first above written.


                               GST TELECOMMUNICATIONS, INC.,
                               a Canadian corporation



                               By:  /s/ Clifford V. Sander
                               -------------------------------------------------
                               Name:          Clifford V. Sander
                               Title:         Senior Vice President, Treasurer
                                              & Chief Accounting Officer


                               TOMEN AMERICA INC.,
                               a New York corporation



                               By:  /s/ Takashi Yoshida
                               -------------------------------------------------
                               Name:          Takashi Yoshida
                               Title:         Vice President


                               TOMEN CORPORATION,
                               a Japan corporation



                               By:  /s/ Morihiko Tashiro
                               -------------------------------------------------
                               Name:          Morihiko Tashiro
                               Title:         Director & General Manager
                                              Electronics & Telecommunications
                                              Division