Mayor Eric Adams conceded Monday that the city has “always” used tax-funded private security guards at overburdened Big Apple migrant centers.

The revelation comes one day after The Post revealed that New York City Health + Hospitals issued a request for proposals to hire a private security company to patrol the packed migrant sites — a gig the rep for city peace officers called “volatile” and “dangerous.”

“We’ve always had security at the shelters, always,” Adams said Monday. “You can’t put thousands of people in a shelter. It would be irresponsible not to have security.

“We’re just making sure we have the people,” he said. “Always making sure we have the security that we need.”

City Hall would not immediately identify the firm it has used nor the cost of the contracts — but a spokesman said the price is figured into the $4.3 billion budgeted over two years.

Gregory Floyd, head of Teamsters Local 237, which represents city peace officers, said Sunday that it’s not a job he or his members want any part of.

“There are migrants who are gang members in these facilities,” he said. “It’s volatile. It’s dangerous. We don’t know if all these migrants are properly vetted. My members are unarmed.”

City officials are currently caring for more than 52,600 migrants — among the more than 84,100 asylum seekers who have been bused into the five boroughs from the US border in recent months.

The number does not include migrants who are staying with relatives or friends.

The city has opened a dozen Humanitarian Emergency Response and Relief Centers and 179 additional migrant services sites to handle the unprecedented tidal wave of asylum seekers — all now at capacity.

Overwhelmed city officials also halted free bus service to a processing center at the Roosevelt Hotel for migrants arriving at the Port Authority Terminal as the daily cost for the crisis is now $7.9 million a day.

Instead, National Guard troops are handing out flyers and telling migrants to walk through Midtown.

Adams says there are now nearly 2,500 migrants flooding into the Big Apple every week, calling it “an unsustainable crisis that we have to constantly be prepared for.”

Nonetheless, he said there have been no major incidents at the sites so far.

“We’re not responding to any spike in crime that’s in our shelters,” Hizzoner said. “We’re making sure we have the manpower as we continue.”