ALBANY – Pressure is building on the two top leaders of the state Legislature to support a stadium on the West Side of Manhattan before Olympics officials visit New York City next month.

Mayor Bloomberg and Governor Pataki are putting on what one insider called a “full-court press” for approval of the project by the state’s Public Authorities Control Board.

That panel, which must sign off on borrowing by certain state agencies, includes representatives of the governor, Assembly Speaker Sheldon Silver, and Senate Majority Leader Joseph Bruno. Opposition from any of those three would be enough to block the state’s proposed contribution of $300 million toward stadium construction.

The vote, expected within six weeks, will come shortly before the arrival of a delegation from the International Olympic Committee, which is considering New York City as the host of the summer games of 2012. The committee is to announce its decision in July.

The decision of the Public Authorities Control Board – while not the final word on the stadium – could determine the success or failure not only of the Olympics bid, but also of Mr. Bloomberg’s broader plans for redeveloping the far West Side.

The proposed stadium, which is to include a retractable roof, would go on top of rail yards owned by the Metropolitan Transportation Authority, adjacent to an expanded Jacob K. Javits Convention Center. In addition to being the principal venue for the Olympics, the facility would become the home field for the Jets’ football team and provide extra exhibition space for the Javits Center. The Jets have committed to pay $800 million toward construction, with the state and the city contributing $300 million each.

Supporters say the stadium would revitalize the neighborhood and stimulate the city’s economy, while critics portray it as a costly boondoggle that would add to crime and congestion on the West Side.

Insiders say that neither Mr. Bruno nor Mr. Silver wants to go to war with Mr. Bloomberg, but that both have misgivings about supporting the stadium.

“I’m having some serious doubts about the entire West Side development project,” Mr. Silver said Wednesday after Mr. Pataki endorsed the stadium in his State of the State speech.

Mr. Silver, whose district includes ground zero, expressed concern that the project might be detracting from efforts to redevelop Lower Manhattan. “There isn’t one square foot of space that is leased in 7 World Trade Center or the proposed Freedom Tower at this point,” he said.

Mr. Bruno, meanwhile, heads a GOP conference that is typically reluctant to subsidize projects in New York City without securing a corresponding benefit for upstate and Long Island.

On Wednesday, Mr. Bruno said it appears to him that the business community of New York City is divided on the benefits of the stadium. “The jury is still out as to what is the best use of that property,” he said.

A spokeswoman for the Jets, Marissa Shorenstein, said team officials remain hopeful that Messrs. Silver and Bruno will both support the stadium. “We continue to work hard to make sure they understand the benefits of the project,” Ms. Shorenstein said.

Today, she said, five elected officials from Queens – three members of the Assembly and two members of the City Council – will announce their support for the project, adding to a list of 60 public officials and dozens of business groups and labor unions who are on board.

The anti-stadium forces also include many public officials, particularly legislators and council members from Manhattan, as well as civic groups and business leaders who would prefer a different type of development on the West Side.

“Putting a 75,000-seat stadium in the most congested borough in the city makes no sense,” Assemblyman Richard Gottfried of Manhattan has said. “Any available site in Manhattan … would produce far more jobs and economic development and tax revenue if it were used for commercial and residential development. Using three square blocks of Manhattan … for a stadium is an outrageous waste of land.”

Supporters and opponents of the project are investing heavily to sway politicians, spending millions on lobbying campaigns and hundreds of thousands on campaign donations. Both sides have hired lobbyists with close ties to the governor and legislative leaders. Among them is Mr. Bruno’s son, Kenneth, who represents Cablevision, the owner of a rival sports facility, Madison Square Garden, and a chief nemesis of the proposed stadium.

A recent study by Common Cause/New York found that in the first eight months of last year Cablevision and Madison Square Garden spent $8.2 million lobbying against the stadium, while the Jets spent almost $3 million lobbying in favor.

The same study found that the owners of Cablevision, Charles and James Dolan, donated $115,300 to various state and city politicians over the past four years, compared to $81,582 from the Jets’ owner, Robert Wood Johnson IV, and its chief executive, L. Jay Cross.

“Any time two very significant interests are going to be on opposite sides of an issue, they’re going to do their utmost to advocate,” a stadium proponent, Assemblyman Michael Gianaris of Queens, said of the lobbying. “There’s certainly a lot of information that’s moving back and forth. So long as one has time to go through all of it, it helps rather than hurts to have the information.”

Assemblyman Steven Cymbrowitz of Brooklyn, a supporter of the stadium, noted that he had received $500 from Cablevision and nothing from the Jets.

“That’s not something I think is making any difference whatsoever,” he said.

Mr. Bloomberg is intent on winning approval for the project as soon as possible, to help persuade Olympics officials that New York City would welcome the 2012 games.

Mr. Gottfried argues the stadium would work just as well in another borough, and that there is no need to make a decision next month.

“No Olympic city has ever started their stadium before they were awarded the Olympics,” he said. “The argument we need to have the shovels in the ground before July is totally bogus. The reason the mayor is raising that argument is he is trying to stampede the decision.”

One private-sector supporter of the stadium, speaking on condition of anonymity, suggested that the governor and legislative leaders could give the stadium tentative approval next month, contingent on the Olympics coming to New York City.

Another observer, Jeremy Soffin of the Regional Plan Association, said, however, that it would be difficult to negotiate such a deal so quickly.

“Everyone acknowledges there’s going to be a lot of horse-trading going on,” Mr. Soffin said. “There’s so much that hasn’t been resolved up in Albany, it’s almost too soon to do the trading.”

Even if the Public Authorities Control Board grants its approval, the stadium still faces obstacles. The Jets must reach agreement with the Metropolitan Transportation Authority on leasing the air rights over the rail yards – a negotiation that is likely to include the Legislature – and stadium opponents have already filed suits challenging the conclusions in an environmental impact study prepared by city officials.