The speaker of the City Council, Gifford Miller, outlined legislation yesterday that could foil Mayor Bloomberg’s financing plan for the West Side stadium.

The bill, which Mr. Miller said he will introduce next week, would prohibit a mayor from spending so-called PILOT money without going through the budget process and would require the administration to report to the council every month outlining all of the PILOT money the city is collecting.

Mr. Bloomberg has proposed paying the city’s $300 million contribution to the New York Sports and Convention Center with the “payments in lieu of taxes” it receives from city businesses. The project would feature a domed stadium to be used by the New York Jets, which would also be the Olympic Stadium if New York becomes host city for the 2012 Summer Games.

“This is the people’s money, this is not the mayor’s money,” Mr. Miller said. “This is not a slush fund that he gets to divide up for pet projects.”

Mr. Miller, who is seeking the Democratic nomination for mayor, said that it is illegal under the City Charter to redirect PILOT money outside the budget, and that the new legislation is needed only to reinforce what’s already on the books.

Mr. Bloomberg has a different interpretation. A spokeswoman for the city’s Law Department, Kate O’Brien Ahlers, said a mayor has the authority to use PILOT money as he “deems appropriate.” She cited both the charter and General State Law 20 and said the authority was “within the mayor’s broad powers relating to economic development and contracting.”

“Any proposed limitation on the mayor’s powers by council action would be illegal,” she said.

The executive director of the Institute for Fiscal Policy, Frank Mauro, who served as director of research for the Charter Revision Commission in the late 1980s, said he did not believe the mayor had the power to use PILOT money freely.

“This is sort of a fundamental separation of powers,” Mr. Mauro said. The “powers of the purse” are in the hands of the legislative body, he said.

“I don’t think this is a matter of liking or not liking Mayor Michael Bloomberg or Gifford Miller,” he said.

Mr. Miller, who has sought to capitalize on the mayor’s perceived vulnerability on the stadium issue by conducting daily news conferences, had prostadium and anti-stadium members of the council by his side yesterday.

The chairman of the council’s finance committee, David Weprin of Queens, a stadium proponent, said the legislation was not a “stadium-stop initiative” and added, “There are other ways the stadium could be paid for.”

Meanwhile, the president of the Jets, Jay Cross, issued a four-paragraph statement yesterday reiterating that the football team “has no intention of building a stadium anywhere but over the rail yards.”