New York City officials blindsided a sleepy Staten Island neighborhood by opening a 300-person migrant shelter at the site of a former Catholic school – where the scent of raw sewage now wafts into the home next door, lawyers charged at a court hearing on Thursday.

Mayor Eric Adams’ administration “didn’t speak to members of the community” before ordering that the former St. John Villa Academy be filled with asylum seekers as migrants pour into the city, alleged Mark Fonte, a lawyer for Staten Island local Scott Herkert, who is seeking a court order to shutter the site.

“They simply saw a vacant building and shoved migrants in,” Fonte said during the hearing in Staten Island Supreme Court.

The shelter’s outdoor showers – which use water heaters running on generators 24 hours a day – pose an “unreasonable public nuisance” to Herkert, 53, and his neighbors, his attorneys argued.

But a lawyer for the city, Chad Hughes, fired back that Herkert’s complaints do not rise to the level of what’s known as an “irreparable harm” that the judge would need to find to order the site closed – while admitting that the city has no current timeline in place for shuttering the shelter itself.

“They don’t want to live near a shelter is basically what this ‘harm’ comes down to,” Hughes told Justice Wayne Ozzi.

“I want to be there with my children, play in the backyard, those kinds of things — really what that amounts to is that he just does not want to live near a shelter.” 

Hughes added that the city is not yet aware of any evidence that the site’s outdoor showers are leaking water into Herkert’s yard, as Herkert alleged in a civil lawsuit filed last month.

“They haven’t told us that there’s any real problem with the showers, that there’s water coming out,” Hughes said.

“There’s no evidence that people are walking around naked outside or in their robes.”

Following the 80-minute hearing, the judge said he planned to issue a written decision in the case in the coming days or weeks – after he gives the matter a “very close look.”

If the court were to order the facility, at Cleveland Place and Landis Avenue, closed, City Hall could still file an appeal.

The Adams administration previously appealed on Aug. 25 and convinced the state’s Appellate Division to order the shelter to remain open hours after Justice Ozzi had issued a temporary order to close it.

Ozzi, during Thursday’s hearing, questioned Hughes about whether City Hall should have a “blank check” to house migrants despite the Big Apple’s “right to shelter” mandate, which since 1981 has required the city to provide housing to anyone who applies for it.

Adams moved in May to temporarily loosen the city’s unique requirements for housing homeless families seeking shelter, amid the escalating migrant crisis.

But the Legal Aid Society has teamed up with former city social services commissioner Steve Banks – who now works at white-shoe law firm Paul Weiss – to oppose City Hall in the case.

City Hall sources have told The Post that the city’s surging migrant population is set to double by June 2024 — meaning the Big Apple will be tasked with housing more than 100,000 asylum seekers — as costs are estimated to rise to a mind-boggling $12 billion over the next three years.

“The city spent about $12 billion to alleviate this,” Ozzi told Hughes during the hearing, before asking aloud: “Should their actions be commensurate with their financial ability to do so? Is it a blank check here?”

As of Sept. 10, the city had opened 208 sites across the city to house more than 59,600 migrants, with more than 3,200 people entering the city’s care within the prior week alone.

Many of the recent arrivals are seeking asylum from political violence and economic chaos in Latin America and Africa.

Herkert’s lawyers, Fonte and Louis Gelormino, also argued during the hearing that the St. John’s Villa site violates local zoning regulations and “unduly burdens” Staten Island with the costs of the city’s homeless housing mandate.

The city also exceeded its authority by declaring a temporary emergency allowing it to order the site to become a shelter, the lawyers claimed.

“The city in its papers said that this is a disaster…but I don’t think by any means of the imagination, when you start to list fire, flood, wind, I don’t think by any means of the imagination migrants should be part of that,” Gelormino told the court.

“An emergency is something that’s sudden and unexpected. This is certainly not so,” the lawyer added. 

Earlier in the day, a crowd of local Staten Island elected officials rallied outside the courthouse, urging the judge to step in and close the shelter.

“Today is about hoping, hoping that at least one branch of government listens to the plea and plight of the people of Staten Island and shuts this thing down,” Staten Island borough president Vito Fossella said during a press conference.

“That’s what we’re hoping for.”

Republican State Assemblyman Michael Tannousis said that he was urging Ozzi “to do what the mayor and governor have not, and that is hear us out, hear our case as to why St. John Villa Academy is the worst possible location for a migrant shelter.”

“We need to have accountability in this process and we have not received any from the City of New York,” Tannousis said.

Additional reporting by Nolan Hicks.