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                                                                       Exhibit 5

                                HALE AND DORR LLP
                               Counsellors At Law
                                 60 State Street
                                Boston, MA 02109

                           617-526-6000 - 617-526-5000


                                  April 4, 2000


Network Plus Corp.
234 Copeland Street
Quincy, MA 02169

         Re:      REGISTRATION STATEMENT ON FORM S-3

Ladies and Gentlemen:

         This opinion is furnished to you in connection with a Registration
Statement on Form S-3 (File No. 333-32040) (the "Registration Statement") filed
with the Securities and Exchange Commission (the "Commission") under the
Securities Act of 1933, as amended (the "Securities Act"), for the registration
of shares of Common Stock, $.01 par value per share (the "Shares"), including
Shares issuable upon exercise of an over-allotment option granted by the
Company, of Network Plus Corp., a Delaware corporation (the "Company"), with a
maximum aggregate offering price of $287,500,000, of which certain Shares will
be issued and sold by the Company and the remaining Shares will be sold by
certain stockholders of the Company (the "Selling Stockholders").

         The Shares are to be sold by the Company and the Selling Stockholders
pursuant to an underwriting agreement (the "Underwriting Agreement") to be
entered into by and among the Company, the Selling Stockholders and Goldman,
Sachs & Co., Bear, Stearns & Co. Inc., Donaldson, Lufkin & Jenrette Securities
Corporation, Merrill Lynch, Pierce, Fenner & Smith Incorporated, Fidelity
Capital Markets, a division of National Financial Services Corporation, and
Kaufman Bros., L.P., as representatives of the several underwriters named in the
Underwriting Agreement, the form of which has been filed as Exhibit 1 to the
Registration Statement.

         We are acting as counsel for the Company in connection with the sale by
the Company and the Selling Stockholders of the Shares. We have examined signed
copies of the Registration Statement as filed with the Commission. We have also
examined and relied upon the Underwriting Agreement, minutes of meetings of the
stockholders and the Board of Directors of the Company as provided to us by the
Company, stock record books of the Company as provided to us by the Company, the
Certificate of Incorporation and By-Laws of the Company, each as restated and/or
amended to date, and such other documents as we have deemed necessary for
purposes of rendering the opinions hereinafter set forth.


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Network Plus Corp.
April 4, 2000
Page 2


         In our examination of the foregoing documents, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals, the conformity to original documents of all documents submitted to
us as copies, the authenticity of the originals of such latter documents and the
legal competence of all signatories to such documents.

         Our opinion in clause (ii) below, insofar as it relates to the Selling
Stockholders' shares being fully paid, is based solely on a certificate of the
Chief Financial Officer of the Company confirming the Company's receipt of the
consideration called for by the applicable resolutions authorizing the issuance
of such shares.

         We assume that the appropriate action will be taken, prior to the offer
and sale of the Shares in accordance with the Underwriting Agreement, to
register and qualify the shares for sale under all applicable state securities
or "blue sky" laws.

         We express no opinion herein as to the laws of any state or
jurisdiction other than the state laws of the Commonwealth of Massachusetts, the
General Corporation Law of the State of Delaware and the federal laws of the
United States of America.

         Based upon and subject to the foregoing, we are of the opinion that (i)
the Shares to be issued and sold by the company have been duly authorized for
issuance and, when such Shares are issued and paid for in accordance with the
terms and conditions of the Underwriting Agreement, such Shares will be validly
issued, fully paid and nonassessable and (ii) the Shares to be sold by the
Selling Stockholders have been duly authorized and are validly issued, fully
paid and nonassessable.

         It is understood that this opinion is to be used only in connection
with the offer and sale of the Shares while the Registration Statement is in
effect.

         Please note that we are opining only as to the matters expressly set
forth herein, and no opinion should be inferred as to any other matters. This
opinion is based upon currently existing statutes, rules, regulations and
judicial decisions, and we disclaim any obligation to advise you of any change
in any of these sources of law or subsequent legal or factual developments which
might affect any matters or opinions set forth herein.

         We hereby consent to the filing of this opinion with the Commission as
an exhibit to the Registration Statement in accordance with the requirements of
Item 601(b)(5) of Regulation S-K under the Securities Act and to the use of our
name therein and in the related Prospectus under the caption "Legal Matters." In
giving such consent, we do not hereby admit that we are in the category of
persons whose consent is required under Section 7 of the Securities Act or the
rules and regulations of the Commission.

                                             Very truly yours,

                                             /s/ HALE AND DORR LLP

                                             HALE AND DORR LLP