NEW YORK CITY — City Hall officials are quietly exploring a proposal to move inmates off Rikers Island and into renovated borough detention centers and two new jails in city neighborhoods, DNAinfo New York has learned.

The move runs counter to public statements made by Mayor Bill de Blasio last month where he called plans to shut down the city's controversial central jail a "noble concept" that was unworkable because it would "cost many billions" to do.

"In the end, you still are going to need facilities," he said. "Where are you going to put them?"

But city officials have identified possible locations on Staten Island, The Bronx, Brooklyn and Queens where two new jails — each housing as many as 2,000 inmates — could be built.

Space next to the NYPD’s newly opened police academy in College Point is one possible location, according to sources.

Another location is in Hunt’s Point on land next to where an 800-inmate jail barge is moored. The barge, known as the Vernon C. Bain Center, would also be shuttered under the plan, sources said.

City officials, who have been studying the idea of a Rikers shutdown for more than a year, have also identified two locations in Brooklyn as possible jail sites, sources said.

The plan could cost as much as $7 billion and would take over a decade to build the new facilities and perform renovations, sources said. In all the entire phase out of Rikers could take 30 years.

Rikers Island’s inmate population hovers around 10,000, but de Blasio has set a goal of reducing the size by a quarter.

Under the Rikers shutdown proposal, the two new jails and rehabbed correctional facilities would hold roughly 7,500 inmates, de Blasio’s target population.

De Blasio spokeswoman Monica Klein said the mayor believes there are "many significant challenges" that must be addressed before Rikers could be closed.

"For years, an environment of violence, abuse and neglect has been tolerated at Rikers," she continued. "The situation is unacceptable and must change now, not another decade from now."

She added that the administration is "putting into place serious reforms, which are reducing violence in targeted areas and keeping the population down. Closing Rikers does not close the jail system, and we need to fix what's inside these buildings — wherever we put them."

'THEY'RE TERRIFIED'

Sources said City Hall officials see the $7 billion cost as an extremely rosy estimate, but perhaps the biggest obstacle to the proposal is the Uniform Land Use Review Procedure, or ULURP.

“They’re terrified of it,” one source said of the public vetting process on how land-use changes would affect their neighborhood.

If the city were to build new jails or make major renovations of existing facilities, then the changes must be approved through a years-long multi-tiered process, which includes votes by the affected community boards and the City Council.

City officials fear the resistance would slow the process to a standstill.

"It's daunting, It's big. It's huge money and it's huge political costs," said another source who helped study the issue for City Hall but asked not to be named to protect relationships. "Opening a homeless shelter is difficult. Imagine dropping a 1,500-person jail in someone's neighborhood."

Glenn Martin, a criminal justice reform advocate and founder of JustLeadershipUSA, said expending political capital seems to be one of the biggest obstacles to closing Rikers.

Martin spent six years in prison and has been named to a commission led by the former chief judge of the state, Jonathan Lippman, to examine a Rikers shutdown.

"We're back to having a very political mayor in office. This is not Mike Bloomberg," Martin said. "The mayor is the main holdout in the growing chorus to close down Rikers."

RESISTANCE ALREADY

And the pushback to building neighborhood jails has already begun — before any ideas have been publicly floated.

After City Council Speaker Melissa Mark-Viverito called for an overhaul of the city’s criminal justice system in her state of the city speech Feb. 11 and announced the formation of the Lippman commission, Councilman Joe Borelli, who represents Staten Island’s South Shore, wrote a letter to the speaker telling her that he doesn’t want a jail in his district.

His concern was that Mark-Viverito’s commission would identify a possible jail site on a tract of land in Rossville along the Arthur Kill that the city Department of Correction owns.

Borelli said he deduced the site would be considered using common sense but was called "crazy" for suggesting it. Over the years, the city's Economic Development Corporation issued a Request for Expressions of Interest for the 33 acre parcel but nothing ever came of it.

Borelli said another idea was floated of doing a land swap with the owners of the adjacent LNG tanks site where the city would trade the Arthur Kill side of the property in exchange for the backside of both properties and create a park.

The Staten Island Advance reported earlier this month that the owner of LNG tanks site hired an architectural firm to develop plans to turn the space into a "regional factory outlet center" with a fast ferry, movie theater and park.

"Somebody really smart decided we're going to put people who are potentially violent criminals on an island away from society. No one wants a jail next to their house," said Borelli, who called for the current Rikers facilities to be modernized to help reduce violence.

"I have not had one complaint from a constituent that visiting their family at Rikers Island was too far," he continued. "If it is, I really don't care. Putting this in an obscure residential part of Staten Island doesn't necessarily help make this more accessible to potential prisoners' families."

Borelli is right about the Rossville site — city officials identified it as a possible location for a new jail, sources said.

'FAIRER, BETTER AND MORE HUMANE'

Mark-Viverito stood behind the importance of shuttering Rikers.

"For too long, Rikers Island has been emblematic of the deep institutional flaws in our city's jail system. New Yorkers deserve a fairer, better, and more humane system that treats everyone with respect and dignity," Mark-Viverito said in a statement.

The City Hall plan, which sources say could save more than $500 million annually, includes spending nearly $3 billion to expand or renovate the detention centers in Manhattan, Brooklyn and Queens.

The Manhattan center would house women, according to sources.

And there are already blueprints for an expanded Brooklyn Detention Center, which had been closed for a decade when it reopened in 2012 with a limited population.

In 2010 Ricci Greene Associates and 1100 Architects created a design for an expanded, state-of-the-art Brooklyn Detention Center for the city’s Department of Correction.

During the Bloomberg administration, then-Commissioner Martin Horn had envisioned reestablishing a community-based jail system where inmates were closer to their families, their attorneys and the courts.

“In Marty’s view, housing all the inmates on Rikers was not the most efficient policy,” said David Burney, who, at the time, was the Department of Design and Construction commissioner and was tasked with overseeing the redesign. “His idea was that what we should really be doing is putting the detention housing next to the courts.”

Burney said moving inmates closer to the courts was more sustainable and would have cut down on the costs of bussing inmates to and from Rikers.

The design would have more than doubled the number of inmate beds at the Brooklyn center to nearly 1,500 from 600.

But the center, which runs along Atlantic Avenue between Boerum Place and Smith Street, was never renovated because of neighborhood opposition. Horn also resigned as commissioner in 2009 before the Ricci Greene-1100 Architects study was completed.

His successor, Dora Schriro, opted against a community-based jail system and instead planned a new $600 million admissions facility at Rikers, which has yet to be built.

“We had done the design. It was ready to go,” Burney said. “But Marty Horn left. Dora came in. Her philosophy was different.”

The source who studied closing Rikers for City Hall said he didn't understand why de Blasio would not take smaller steps as part of a compromise.

"Politically, it was disastrous not to say well, we can't move everybody but dammit we're going to move the juveniles," the source said. "You can take off a couple of other populations, the women's population, the mentally ill. You could maybe come to some place in between."