If the president of Brooklyn has his way with the Brooklyn House of Detention, there will be apartments built to share the Boerum Hill space with a new, smaller jail.

Marty Markowitz wants to raze the 800-bed jail on Atlantic Avenue and sell about three-quarters of the site’s development rights. The proceeds would be used to build a more efficient jail near the back of the lot, hidden behind a new mixed-use building.

The proposal follows an announcement last year that the Department of Correction would seek to reopen its Brooklyn facility, which has been closed since 2003. The city has said it is considering using the ground floor for 24,000 square feet of retail space, but it also will consider completely ridding the growing neighborhood of one of its biggest eyesores. On Friday, Mayor Bloomberg signaled that the latter was a possibility.

Mr. Markowitz told The New York Sun yesterday that he has a “bold vision” for a “signature building” on Atlantic Avenue featuring residential, commercial, and retail areas, and possibly a hotel. He said he would support nothing less than tearing down the existing jail and building something new.

“We feel we are now in 2006 – March – this is the hottest real estate market Brooklyn has known in generations,” Mr. Markowitz said. “If we have to have it, it would be foolish if the city does not take advantage of this super hot real estate market and go out to the development community.”

The borough president has shown the plans to Mr. Bloomberg and said he wants the city to put out a request for proposals this year. “We are pushing it, promoting it, and I’m using the bully pulpit of my job,” he said.

Mr. Markowitz said he has spoken with several area developers who say they are interested in the site. He said he had not consulted with the developer of the Atlantic Yards project, Bruce Ratner.

A spokesman for the Department of Correction, Thomas Antenen, said all options are on the table. He said the future of the prison, which underwent extensive renovations recently, depends in large part on population projections for the city’s existing jails. Mr. Antenen said a rise in the existing population of inmates could trigger the need to immediately reopen the Brooklyn facility. The same could be true if there is a decrease in jail space, which will occur when a Bronx prison barge comes out of the water next summer of 2007.

The local City Council member, David Yassky, a Democrat, said a thaw in the Department of Correction’s position has made real the possibility of razing the building.

“The Department of Correction finally recognized they are occupying a hugely important space in downtown Brooklyn,” he said.

The director of the local advocacy group Downtown Brooklyn Council, Michael Burke, said he has been shopping the prison redevelopment proposal around to business and residential groups and the city government, including City Hall.

“It’s not a NIMBY. We accept the responsibility in downtown Brooklyn for civic uses, that’s part of the fabric of any downtown, and perhaps a jail fits into that category,” Mr. Burke said. “If so, make it as efficient and unobtrusive as possible.”