Interior Secretary James G. Watt yesterday officially notifed the House Interior Committee that he will proceed with Wednesday's offering of leases to 540 million tons of federally owned coal in North Dakota despite the committee's vote last month directing him not to do so.

Watt said in a letter to committee Chairman Morris K. Udall (D-Ariz.) that the directive was unconstitutional because of the Supreme Court's recent ruling voiding the one-house legislative veto. Assistant Interior Secretary Garrey Carruthers said in a briefing yesterday that the agency has studied the tracts to be leased for more than four years, and that this should answer the House committee's concern over possible environmental damage.

This is one of the first cases in which the government has invoked the one-house ruling to take actions opposed by a congressional panel. Two environmental groups have attempted to block the leases on the ground that the high court's ruling does not apply, and a federal judge is to hear arguments in the case on Oct. 21.

Interior officials stressed, however, that this will not delay the program. The leases being offered Wednesday could not actually be issued, they said, until after the court hearing.