A federal appeals court has overturned a legal order requiring Florida and the US President Donald Trump's administration to shut Alligator Alcatraz, allowing the immigration detention centre to stay open.

In a 2-1 ruling, the appellate court in Atlanta, Georgia, granted a request from the state of Florida and the US Homeland Security Department to block a lower court injunction while a lawsuit plays out.

"Alligator Alcatraz is, in fact, like we've always said, open for business," said Florida Governor Ron DeSantis.

Last month, US District Judge Kathleen Williams ordered a halt to the facility's expansion and for its dismantling to begin within 60 days.

Judge Williams, who was appointed by former President Barack Obama, agreed with environmental groups and a Native American tribe that had argued the facility should have undergone federal environmental reviews.

The Department of Homeland Security had begun transferring detainees out of the Everglades, a Unesco World Heritage Site, late last month in compliance with that court order.

But on Thursday, the US Court of Appeals for the 11th Circuit concluded that state and federal officials would probably succeed in showing the facility was not subject to the National Environmental Policy Act because it had not yet received any federal funding.

Two Trump-appointed judges wrote the majority ruling. An Obama-appointed judge dissented.

The virtually abandoned Florida airport in the sensitive wetlands was transformed into a detention centre in July.

The homeland security department said the appellate ruling was a "win for the American people, the rule of law and common sense".

"This lawsuit was never about the environmental impacts of turning a developed airport into a detention facility," the department wrote in a post on X.

"It has and will always be about open-borders activists and judges trying to keep law enforcement from removing dangerous criminal aliens from our communities, full stop."

Florida's Republican governor also welcomed the decision.

"Some leftist judge ruled implausibly that somehow Florida wasn't allowed to use our own property on this important mission because they didn't do an environmental impact statement," DeSantis said.

A lawyer for the Center for Biological Diversity, one of the plaintiffs in the lawsuit, said the decision was "a heartbreaking blow to America's Everglades and every living creature there, but the case isn't even close to over".

Friends of the Everglades, another plaintiff, said that was reviewing the order.

The third plaintiff, the Miccosukee Tribe, which argues the facility threatens its ancestral land, has not yet commented.