NEW YORK - The New York Yankees will soon unveil plans to build a new $700 million, open-air stadium across 161st Street from its historic home in the Bronx, according to team executives and elected officials, and the team is willing to pay nearly all the costs of construction.

The team continues to tinker with the plan, but intends to present a final proposal to Mayor Michael R. Bloomberg and Gov. George E. Pataki in the coming weeks.

The new, slightly smaller ballpark, with about 50,000 seats and 50 luxury boxes, would be built in Macombs Dam Park, just to the north of the existing stadium, an American sports shrine.

Unlike previous proposals, the existing stadium - which opened in 1923 and has been the site of 33 World Series - would not be demolished, at least not most of it. It would be converted, possibly, to a multi-level parking garage with a soccer field on top, while retaining the ballfield and the most recognizable elements of the structure.

Although the Yankees are drawing nearly 3.5 million fans a year at their aging, outmoded home in the Bronx, the team's principal owner, George Steinbrenner, has long wanted a modern stadium, with wider concourses, restaurants, more luxury boxes and club seating that would generate millions more in revenue and increase the value of the team.

The new stadium would have about 6,000 fewer seats than the current stadium, but far better sight lines for fans, according to executives who have seen the plans. The team also saved money from an earlier proposal by eliminating a retractable roof, a feature that could cost $200 million.

The proposal dovetails with a redevelopment scheme sponsored by Bronx Borough President Adolfo Carrion for the hardscrabble neighborhood, which includes a site for a hotel, retail shops, commercial development, a Metro-North station, an upgraded ferry terminal on the Harlem River and a shopping mall at the Bronx Terminal Market.

Neither the Yankees nor city officials were willing to comment publicly on Thursday on the details of the proposal. But the Yankees showed their plans to city officials earlier this month and the team conceded that a proposal is in the works.

"The Yankees are continuing to plan for a new stadium," said Randy Levine, president of the Yankees. "We're speaking with many people in government and in the community. But we don't have anything to present yet."

Carrion, who was in Boston for the Democratic convention, said he would soon release a comprehensive plan for the area surrounding Yankee Stadium.

"We've been talking to the Yankees for two years," he said. "There's some pretty serious planning brewing here. We'll be able to give a full-blown presentation pretty soon."

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The Yankees' latest proposal is a remarkable turnabout for a legendary ballclub that once threatened to abandon the Bronx for New Jersey, unless the city and state helped it build a $1 billion stadium on the west side of Manhattan. It seems to take into account new political realities and the volatility of government subsidies for sports buildings among the public.

At the same time, the team's plan is likely to provoke greater scrutiny of plans for the city and state to provide a $600 million subsidy for a $1.4 billion, 75,000-seat stadium for the New York Jets and to do $187.7 million in road and railyard work for the proposed $435 million Nets arena in Brooklyn.

"The most recent proposal from the Yankees indicates a sea change in their thinking, recognizing that the public doesn't want to subsidize stadiums given the city's other more pressing needs," said Harvey Robins, a former aide to mayors Edward I. Koch and David N. Dinkins. "As the Yankees put more on the table, I'd like to see comparable concessions from the Jets and the Nets."

If the Yankees proposal is adopted, the team's $700 million investment in the stadium would represent both the most expensive baseball park and the largest such investment by a professional baseball team. But in recent years, as economists questioned the wisdom of public investment in stadiums that mostly enrich the owners, sports teams have increasingly been forced to pay a larger share of the stadium costs once borne by cities and counties.

Given New York's recent fiscal constraints, the Bloomberg and Pataki administrations declared that they would not pay for sports buildings themselves, although they would be willing to consider infrastructure improvements like roadwork and public transportation.

At the end of his term in 2001, Giuliani tried to seal a deal to build new $800 million stadiums for both the Yankees and the Mets, in which teams would pay half the cost, or $400 million each. The Yankees would have built a new 47,000-seat stadium with a retractable roof in Macombs Dam Park and demolished the old stadium. Under that deal, the state was expected to spend an additional $390 million on parking garages, highway improvements and public transportation for the stadiums.

But after Bloomberg succeeded Giuliani, inheriting a recession and a city wounded by the attack on the World Trade Center, he quickly said there was no money for stadiums.

Since then, the city backed the plan for a Jets stadium, which would also serve as an Olympic stadium if New York wins its bid for the 2012 summer Olympic games, and the Nets arena proposal.

Like the Jets and the Nets, the Yankees may also ask the city to issue tax-exempt bonds for the project. The team, however, would make the annual payments on the bonds.

Still, the state would probably have to spend tens of millions to build the Metro-North station and extend subway platforms for the new stadium, as well as a number of highway improvements. The team's plan envisions a large, multi-level parking garage, which could be built by the state or a private owner. The Metro-North station could, however, reduce the total number of parking spaces needed by the Yankees.

The team has also worked with Bronx officials to map out a series of parks and ballfields to replace Macombs Dam Park and sidestep potential community opposition.

One executive who was briefed by the Yankees said the whole project was made possible by the team's financial plan. One of the most valuable sports franchises in the world, the Yankees paid about $60 million in revenue-sharing money to Major League Baseball. The league's rules allow teams to subtract annual stadium costs from their revenue-sharing obligations. So the Yankees would pay, say, $40 million a year to repay the bonds, rather than handing it over to MLB.

"The team can shoulder most of the costs," said one person who has seen the Yankees' plan. "The beauty of this transaction is the fact that money spent towards stadium construction is viewed as an operating cost and isn't subject to revenue sharing."