A judge on Staten Island temporarily blocked New York City on Tuesday from using a former school as an emergency shelter for migrants, in a decision that could have broader implications for the city’s long-established obligation to offer shelter to anyone who asks for it.

The city has struggled to provide housing to the more than 110,000 migrants who have entered its shelter system since early last year, in part because of a decades-old legal obligation, known as “right to shelter,” that requires it to provide a bed for anyone who is homeless and asks for one.

Citing “right to shelter,” Mayor Eric Adams issued an emergency order that allowed the city to bypass the typical process required to open a new shelter for homeless people. But on Tuesday, Justice Wayne Ozzi of State Supreme Court wrote that the “right to shelter” does not exist, and ordered the Staten Island school emptied.

The ruling came in a suit filed last month against the city and state by a man who lives near the school and eight Republican city, state and federal elected officials who represent the island, New York City’s most conservative borough.

A spokeswoman for the mayor said the city would “immediately appeal this ruling, which we believe is incorrect in key respects and which threatens to disrupt efforts to manage this national humanitarian crisis.”

Joshua Goldfein, a staff attorney for the Legal Aid Society, which filed the litigation that led to the right to shelter, said of Justice Ozzi’s ruling, “The decision in Staten Island is wrong on the law, on the facts. We do not expect it to stand.”

The shelter is housed in a former Catholic school, St. John Villa Academy, that the city now owns. The city said last week that 72 migrants are staying there. Justice Ozzi ruled that his order, a preliminary injunction, would take effect “immediately” as soon as the plaintiffs pay a $25 fee.

The ruling could complicate matters for the city. It has been arguing in the Staten Island case that the crisis requires it to house migrants in the school. The city has opened more than 200 makeshift homeless shelters in hotels, tents, office buildings and other structures to accommodate the newcomers.

But in a separate case it is arguing, before another judge in State Supreme Court — which in New York, unlike other states, is beneath other courts — the city has been asking for relief from the right-to-shelter rule, which would effectively block some migrants from being eligible. A hearing in that case was held on Tuesday afternoon.

Mr. Adams has said that the cost of dealing with the migrant crisis could “destroy” the city. Gov. Kathy Hochul said this month that the right to shelter negotiated in the 1980s was never intended to be “an unlimited universal right or obligation on the city to have to house literally the entire world.”

Louis Gelormino, one of the lawyers for the homeowner and politicians who brought the Staten Island suit, said on Tuesday that he believed the judge’s ruling effectively overturns the right to shelter entirely.

“In essence, the judge gave the mayor exactly what he wanted,” he said.

The city Law Department declined to say whether it believed that Justice Ozzi’s ruling had that effect.

The case has already been through one round of legal battles from which the city emerged victorious. Last month, before the shelter opened, Justice Ozzi issued a temporary restraining order blocking it from placing migrants at the school. The city immediately appealed and an appeals judge ruled in its favor.

The Staten Island shelter has become a central location for the growing opposition to migrant shelters around the city, drawing weeks of protests. At one point, opponents had rigged up a speaker outside the shelter that broadcast messages at ear-piercing volume, including one saying “immigrants are not safe here.”

The homeowner who filed the suit, Scott Herkert, 50, who lives next door to the school, said on Tuesday that the shelter “was shoved in our face with no input from the community.”

He added, “We have a real problem that needs to be addressed by both sides of the political divide. This is not just me. It’s Staten Island, it’s the city, it’s the country. Something is wrong. And it’s wrong everywhere.”

Mark Bonamo and Erin Nolan contributed reporting.