The city’s largest homeless shelter for men — housing 250 residents in Manhattan — will close by the end of next month, Mayor Zohran Mamdani announced Thursday.

The city-owned Bellevue shelter on 30th Street has fallen into what the Mamdani administration called a “severe state of disrepair.”

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The building will be shuttered by the end of April, City Hall said — noting the hundreds of current residents would be relocated, without revealing where they’d be sent.

“My administration is focused on ensuring every New Yorker experiencing homelessness not only has access to shelter, but to spaces that are safe, humane and truly livable. We cannot accept a system that treats people without dignity or stability,” Mamdani said in a statement.

The abrupt announcement sparked immediate concern from one of the city’s most prominent homeless advocacy groups, which called the short-notice closure a risk that could cause confusion and deter individuals in need from seeking help.

“For decades, the 30th Street facility has served as the primary intake center for adult men and adult families across all five boroughs,” said the Coalition for the Homeless and Legal Aid Society in a joint statement.

“Any disruption to this critical front door to shelter — especially on short notice — risks creating confusion and additional hardship for people who are already experiencing homelessness.”

Some residents of the men’s shelter told the Post Thursday they hadn’t been warned the closure would be taking place in a matter of weeks. 

“I didn’t know we were going to leave so quickly–they said the building’s shutting down. They didn’t say exactly when,” Melvin Holmes, 35, said outside of Bellevue. 

“I thought I had time,” the Brooklyn native said, noting he had been at the intake center for over a month and was hoping to soon find a job and an apartment. 

Others acknowledged the deteriorating conditions and vermin infestation in the historic building, which was constructed in 1931. 

“I see a lot of cockroaches and rats,” said 20-year-old Nuru Gawara, who arrived at the shelter Wednesday and has been homeless for about two weeks.

“It’s not that clean. It’s better than nothing. It’s better than being on the street,” Gawara said.

City Hall said the Department of Social Services and the Department of Homeless Services were working to relocate residents by mid-March.

Intake for single adult men will be moved to a facility in the East Village, at 8 East Third St., beginning May 1, officials said. Intake for families without minors will be relocated to 333 Bowery on the same date.

DHS will maintain a “small presence” at the Bellevue site for at least one year after closure to aid those who may come seeking shelter, officials said.

“Direct transportation will also be available throughout the day,” a spokesperson for the mayor told The Post.

The city is planning to engage in a “large-scale communications campaign” aimed at informing the public about the move, too, officials said.

City Hall blamed the sudden move to close the shelter on the administration of Mamdani’s predecessor, Mayor Eric Adams.

“Toward the end of the last administration, new shelter sitings stopped almost entirely – and as a result, the current administration inherited several shelter sites that had been neglected for years,” City Hall said in its press release.

— Additional reporting by Greg Carlton and Steven Vago