Hoping to end a months-long stalemate with the Port Authority over construction at the World Trade Center site, developer Larry Silverstein says he will put up millions more of his own money to help move the mega-project forward.

Unable to secure the loans necessary for three mammoth office towers he hopes to build on the eastern half of the  site, Silverstein has been trying for months to convince the Port Authority, which owns the land, to help finance the towers’ construction. In his latest offer, he would contribute $150 million to $250 million towards building two of the three towers, more than tripling his previous offer of $50 million.

Additionally, Silverstein said he was willing to abandon plans to build the 79-story Tower 2—at the corner of Vesey and Church Streets—in favor of the shorter and less expensive Tower 3, a source familiar with the offer told the Trib. The switch would net a saving of more than $262 million.

The 78-year-old developer, who signed a 99-year lease on the Trade Center six weeks before it was destroyed, made his latest offer during a meeting last month with the Port Authority and city and state officials. Silverstein spokesman Dara McQuillan credited Gov. David Paterson with reinvigorating the negotiations.

“We hope the governor’s initiative will lead to continued productive conversations,” McQuillan said.

A spokesman for the Port Authority declined to comment on the offer.

Silverstein offered his proposal just two weeks after an arbitration panel ruled against him, saving the Authority from having to pay the developer millions of dollars in damages and rent relief. He had filed for arbitration against the Authority in August of last year, claiming that delays on the agency’s part in delivering construction-ready land along Church Street for the three office towers prevented the developer from securing loans for the buildings before the credit markets collapsed in 2008.

But the three-member arbitration panel determined that although the Port Authority was more than a year-and-a- half late when it finally turned the sites over in August, the agency had met all of its primary obligations to Silverstein.

Now, with the prospect of a payout from the Authority gone, Silverstein said he is not only willing to put in more cash, but that he will use Liberty Bonds and insurance money allocated for all three towers to back loans for two buildings.

While the Port Authority has not officially responded to Silverstein’s latest offer, it seems unlikely that it will accept it. A source familiar with the agency described its initial reaction as “not particularly favorable” because the cash offer still falls well short of the $600 million the Authority asked Silverstein to contribute last summer.

In a weekly radio address, Mayor Michael Bloomberg said it was “time to stop this craziness,” and scolded the Port Authority for apparently dismissing Silverstein’s offer.

“We asked [Silverstein] to come up with more money, and he did,” Bloomberg said. “Now it’s the Port Authority’s turn.”

According to the arbitration panel’s decision, Silverstein and the Port Authority have until March 12 to produce a new construction schedule and financing plan for the site’s eastern half. In addition to the 1,776-foot office tower at One World Trade Center and $3.2 billion transportation hub, the Authority is responsible for almost all the underground infrastructure and utility work on the 16-acre site, projects critical for Silverstein because they will determine when his buildings are ready for occupancy.