Low-income residents of a tower that may be erected above a historic Upper West Side church would enter the building through a different door than owners of market-rate condominiums, and would not have access to the gym, playroom, or media center on the condominium’s amenities floor.

Some in the neighborhood are hailing the project as a silver bullet because it would generate enough money to cover West-Park Presbyterian Church’s renovations and upkeep while ensuring that the affordable units remain accessible to low-income New Yorkers in the long-term. Others are calling the separation according to income level a distasteful form of segregation.

The proposal was presented to members of a Community Board 7 committee earlier this week.

Richman Housing Resources has agreed to purchase the air rights above the historic church for about $15 million. The blond-brick tower the developer plans to build atop the 19th-century red stone church would contain 50 studio apartments for individuals ages 55 and older and making $24,000 or less a year; and 27, one-, two-, and three-bedroom condominiums to be sold at market rate. Two- and three-bedroom apartments in the neighborhood regularly sell for more than $1 million.

Under the plan, there would be a third entrance for those entering the church, on West 86th Street at Amsterdam Avenue.

The studio rentals — to be managed by Goddard Riverside Community Center — would be on floors five to 10, and the condominium would occupy the fourth floor and floors 11 to 21, the president of Richman Housing Associates, William Traylor, said. “In my mind, this is the most reasonable and rational way to accomplish what we’re trying to do here, which is enormously complicated,” he said.

Mr. Traylor said the plan ensures that the affordable housing units would not be subject to assessments and fees imposed by the condominium board; and the studios could not be converted into market-rate housing at a later date.

While Mr. Traylor said he expects that low-income housing tax credits from the city could fund the affordable units in full, a West 86th Street resident, Thomas Vitullo-Martin, said city dollars should not be used “at a site that is segregated, that keeps wealthy people from poor people.” Mr. Vitullo-Martin is a member of Friends of West-Park Presbyterian, a neighbors’ group that opposes tearing down any portion of the Romanesque church. If the project goes forward, the easternmost portion of the church would have to be torn down.

The executive director of Goddard Riverside, Stephan Russo, said he supports the project in its current form because it would create much needed affordable housing for seniors. He said more than 2,000 older adults are on the waiting list for units, such as those that will be created above the church. “The reality is that it is very, very hard when you’re building condo units that sell for over $1 million to mix it with low-income housing,” Mr. Russo said. “In an ideal world, perhaps, but we don’t live in an ideal world.”

He said residents of the units above West-Park Presbyterian would have some community meeting rooms in the new building, and would have easy access to classes and services at its senior center located three blocks away.

But a spokesman for New York Acorn, an affordable housing advocacy organization, Jonathan Rosen, said the proposal “brings a type of social exclusion that really has no place in the city in this day and age.”