St. Vincent’s Hospital Manhattan disclosed detailed plans yesterday for the $700 million “green” facility it hopes to build that would replace its aging medical center in Greenwich Village.

Ending months of speculation, St. Vincent’s outlined plans to construct a 21-story hospital across the street from its facility on Seventh Avenue, on a site between 12th and 13th streets that is occupied by the O’Toole Building. Together with a plan to raze the old facility and build luxury housing on that site, the 625,000-square-foot hospital would be part of the largest development project in Greenwich Village in 50 years, a phenomenon — and a concern — not lost on nearby residents.

Unlike the public outcry over condominium and hotel developments in recent years, however, this project pits neighbors against a hospital where many have received care. Concern over a new medical facility also follows an uncertain period for hospitals citywide, after the New York State Commission on Health Care Facilities in the 21st Century last year recommended closure for nine New York hospitals, five in the city. The construction is also part of a larger reorganization plan conceived by the operator of St. Vincent’s, Saint Vincent Catholic Medical Centers, which emerged from bankruptcy in August.

At the crux of the community’s concern, therefore, is not whether St. Vincent’s should stay in the neighborhood and update its facility, but rather how the proposed construction would change the neighborhood’s historic landscape.

“We’re all in agreement that St. Vincent’s needs to stay on and modernize,” the executive director of the Greenwich Village Society for Historic Preservation, Andrew Berman, said yesterday. “The big concern is that it is going to be very big. It’s the size of the new hospital, plus the hundreds of thousands of square feet of luxury housing.”

Last night, the president and chief executive officer of Saint Vincent Catholic Medical Centers, Henry Amoroso, reiterated the hospital’s position that its current facility cannot physically accommodate the necessary upgrades. The current hospital comprises seven separate buildings, with the oldest, the Nurses Residence, dating back to 1924. “Our floor plates are really too small to accommodate the high-tech equipment needed today,” Mr. Amoroso said.

The new plans, with fewer square feet than the current hospital, would offer increased floor space. It would also house 365 beds, 18 operating rooms, and a state-of-the-art emergency room and trauma center.

Officials said financing would come from a fund-raising campaign and the sale of its old facility to the Rudin family for an undisclosed amount. For their part, the Rudins plan to raze the old hospital to make room for 650,000 square feet of high-end housing, or an estimated 450 units. According to preliminary plans, the development includes 19 mid-block townhouses, a mid-rise building, and a 21-story building fronting Seventh Avenue. There would also be 15,000 square feet of street-level retail space, underground parking, and 22,500 square feet of medical office space.

For months, residents of Greenwich Village have expressed reservations about the project, and last night they aired concerns about a lack of affordable housing. Others were pleased, however, with apparent changes made to the hospital plans that were a product of conversations between hospital officials and a community working group.

Prior to last night’s presentation, Mayor Koch — who was recently named co-chairman of a group supporting the redevelopment plans, Friends of the New St. Vincent’s — emphasized that the hospital is trying to be transparent in its plans moving forward. “Community opposition is to be expected particularly in Greenwich Village, to any structure where it is a large structure,” he said. “I think that the community needs them,” he also said, referring to the hospital.

Last month, a hospital-commissioned survey of 600 people living inside its service area indicated that 60% of Greenwich Village residents supported the redevelopment plans.

To be sure, the hospital faces a lengthy approval process.

Complicating the typical development considerations is the fact that the neighborhood is a designated historic district. As such, the plans must receive approval from the Landmarks Preservation Commission before the hospital seeks zoning approval from the Department of City Planning. The City Council has final say over whether the plans may go forward, and Community Board 2 is expected to hold public hearings and to weigh in on the plans as they move through city agencies.

Yesterday, hospital officials said they expect to file plans with the Landmarks Commission by January, and that final approval is not anticipated until the middle of 2009.

Despite such complexities, St. Vincent’s has navigated similar hurdles before, in the late 1970s and early 1980s when the hospital built the Coleman and Link buildings.

In 1979, the hospital received a large-scale community facility designation, a zoning tool that accommodates multi-block campuses such as hospitals and universities. Hospital officials said yesterday that under the new plans, that designation must be removed.

“I think in the end, if you look at this plan and what’s there now, I don’t know how anyone can say this isn’t an improvement,” the president of the Real Estate Board of New York, Steven Spinola, who is familiar with the plans, said. “It’s a design that better relates to the community than the current one, and it gives the hospital something that they can use to continue to service the neighborhood.”