Gov. Kathy Hochul has formally sided with Mayor Eric Adams in his attempt to roll back the city’s “right to shelter” rule in the face of the migrant surge overwhelming the Big Apple, The Post has learned.

“Despite unprecedented resources deployed by the City and the State to assist the newly arrived Migrants, the current situation is not sustainable,” an attorney for the governor’s office filed in Manhattan Supreme Court Wednesday.

While Hochul has recently said she supports changing the decades-old mandate, the new filing is the first time she has backed the mayor’s monthslong legal effort to exclude migrants from having a right to get free housing from city government.

“The City entered into the Consent Decree over forty years ago,” the letter reads. “The parties to the Consent Decree could not have contemplated that the City would experience the influx of so many migrants in such a short period of time.”

“The State Defendants agree that flexibility is imperative to address the surge of migrant arrivals,” attorneys for Hochul write, adding the state supports “the City’s letter application for leave to move for a modification of the Consent Decree.”

Mayor Adams asked the court last week to allow for an exemption from the rule for asylum seekers with thousands arriving each week.

Since the start of the crisis, nearly 125,000 migrants have come to Big Apple and more than 60,000 still remain in the city’s care.

The crisis is projected to cost NYC $12 billion over the next few years without any assistance from the federal government.

“To be very clear, the city is not seeking to terminate [the right to shelter]; we are simply asking for the city’s obligations to be aligned with those of the rest of the state during states of emergency,” Adams said in a statement last week.

“And throughout this crisis, not a single family with children has been forced to sleep on the streets,” he continued, adding, “But as we have said repeatedly, with upwards of 10,000 asylum seekers continuing to arrive every month, New York City cannot continue to do this alone.”