The speaker of the City Council, Gifford Miller, said yesterday that some developers are interested in building on the proposed stadium site on Manhattan’s West Side but won’t come forward for fear that the Bloomberg administration will sabotage their other projects.

“I have been told by at least three major developers in this city that they would bid significantly more than the Cablevision money that’s on the table right now if they were not so absolutely certain that doing so would grind to a halt anything else that they were doing in the city of New York,” Mr. Miller told reporters at a news conference outside City Hall.

“I’m talking about three people that are eminently capable of getting a line of credit for significantly more than $600 million in about an hour,” he said. Mr. Miller would not provide the developers’ names, because, he said, “they’re terrified.” A spokeswoman for the Bloomberg administration, Jennifer Falk, said yesterday: “It is very convenient for the speaker to make baseless accusations without providing any way to substantiate them.”

Mr. Miller, a Democrat who wants to challenge Mayor Bloomberg in November’s election, has been criticized by opponents for taking his position on the stadium late in the process and for straddling issues for political gain.

Yesterday he said he would not support the proposed Jets stadium on the West Side because the bidding process for development rights at the site has not been truly competitive. It would make more economic sense to build a stadium for the football team in Queens, the council speaker said.

Other mayoral contenders have been hammering the mayor on the stadium issue daily as well. A former borough president of the Bronx, Fernando Ferrer, who is considered the front-runner for the Democratic Party nomination, has called the bidding process “rigged” and earlier called for a referendum on the question of using public money to help build the Jets stadium. Rep. Anthony Weiner starting pushing a Queens stadium even before Mr. Miller went public with his stance on the 75,000-seat domed stadium.

The Bloomberg administration believes the New York Sports and Convention Center is crucial to the city’s bid for the 2012 Olympics and has argued the facility would be a boon for the economy.

Meanwhile, Council Member Bill de Blasio, who represents parts of Brooklyn and is hoping to take over as the next speaker, said he would endorse Mr. Ferrer for mayor rather than Mr. Miller. That comes after the state attorney general, Eliot Spitzer, said last week he would back Mr. Ferrer.

Mr. Miller has the backing of a group of Brooklyn council members and over the weekend, Rep. Carolyn Maloney said she would endorse him.