PORTLAND — The secretary of state’s office must address whether some of the petitions used to get the proposed $1 billion New England Clean Energy Connect onto the November ballot were invalid.

Superior Court Justice Michaela Murphy this week gave Secretary of State Matthew Dunlap until April 1 to determine the validity of signatures gathered by opponents of the proposed utility corridor in western Maine.

A lawsuit contends notaries hired by opponents of the project engaged in other campaign activities, violating state law and possibly invalidating some of the signatures. Evidence includes depositions from a state official and lawyer who contend their signatures were forged.

The anti-corridor referendum question could be stricken from the November ballot if enough signatures are invalidated.

Project opponents submitted more than 70,000 signatures, far exceeding the threshold of the 63,000 or so required to make the ballot. But 12,000 signatures were thrown out, and the lawsuit contends another 6,600 could be invalid.

Dunlap, whose office declined comment on the judge’s order, said previously that state law could’ve been violated but that his staff did not have the time to fully investigate before the March 4 deadline.

Central Maine Power’s New England Clean Energy Connect would allow up to 1,200 megawatts of Canadian hydropower to reach the regional power grid to meet Massachusetts’ green energy goals.

Under the proposal, most of the transmission line would follow an established utility corridor, but a new path would be cut through 53 miles  of wilderness that the power company owns.