TRENTON, N.J. — Democratic and Republican lawmakers on Monday filed a lawsuit seeking to halt GOP Gov. Chris Christie’s $300 million statehouse renovation.

Democratic state Sen. Ray Lesniak and Republican state Sens. Christopher “Kip” Bateman and Michael Doherty filed the suit Monday in Superior Court.

The lawmakers argue Christie’s renovation should have been subject to legislative approval and that the plan violates the separation of powers required by the state constitution.

Instead, the renovation was authorized in April by the State Capitol Joint Management Commission. That panel, which includes Democratic and Republican legislative staffers and administration officials, approved up to $300 million in bonds to be issued by the Economic Development Authority to pay for the project.

Christie has called the executive wing of the building a firetrap and says the renovations are necessary because parts of the building have not been significantly updated in six decades. The oldest section of the building dates to the 18th century.

During part of a presentation by the architectural and planning firms Nelson and PDP in April, the Joint Management Commission heard that one of the building’s skylights was held together by yards of tape.

“This is the most ingenious use of duct tape I’ve ever seen in my life,” PDP partner George Skarmeas said at the hearing.

The renovation has become an issue for Democrats and Republicans running to succeed Christie, who is term-limited.

Lesniak is a candidate for governor and has railed against the project for months. Christie’s lieutenant governor, Kim Guadagno, is a Republican candidate and has promised she’d scrap the project if elect.

Christie’s administration didn’t respond to requests for comment.