Exhibit 23.3 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation by reference in this registration statement (Registration No. 333-62094) of our report dated January 25, 2001 included in KeySpan Corporation's Form 10-K for the year ended December 31, 2000 and to all references to our Firm included in this registration statement. ARTHUR ANDERSEN LLP New York, New York May 16, 2001