The Coalition of 9/11 Families filed a lawsuit yesterday in a last-ditch attempt to force the Lower Manhattan Development Corporation and the Port Authority to halt construction at the World Trade Center site until preservationists have fully assessed the historic value of the towers’ remains.

The lawsuit, filed at the U.S. District Court in Lower Manhattan, charges that the rebuilding agencies violated the National Preservation Act and broke pledges made in binding plans for the site.

“LMDC’s decision to allow the Port Authority to proceed with the demolition, removal, or alteration of the subgrade slab and column remnants in the northwest corner of the WTC site without first ensuring that appropriate records are made that comport with the Secretary of the Interior’s Guidelines for Architectural and Engineering Documentation, is arbitrary, capricious, and in violation of [the National Historic Preservation Act],” the lawsuit charges.

Unless all construction and deconstruction stops, the family members will be “irreparably harmed,” the suit says.

“We are deeply disappointed that they would take this action,” said a joint statement issued by the Port Authority and the LMDC.

The Port Authority, which owns the 16-acre site, and the LMDC, the state agency charged with overseeing the rebuilding and memorial processes, have worked closely with the family groups and have made many concessions, the statement said.

For example, officials have committed to preserving artifacts from the remnants of the trade center parking garage, uncovering the box beams that outline the towers’ footprints, and providing the victims’ family members the opportunity to view them.

Outside the Lower Manhattan courthouse yesterday afternoon, a small group of family members said officials make promises at private meetings but don’t keep them.

“There are laws in place to protect historic treasures like these,” said one of the plaintiffs, Anthony Gardner, who lost his brother in the terrorist attack of September 11, 2001.

He said rebuilding officials did not made any attempt to document or preserve the box beams before starting construction.

Rather, he said, they’ve drawn up legal papers “with so much wiggle room that they’re essentially meaningless.”

The first hearing in the case will be scheduled next week, a lawyer for the group said.