A US appeals court has rejected former president Donald Trump's effort to keep prosecutors from examining thousands of government documents he held in his Florida home after leaving office.

The federal appeals court in Atlanta, Georgia, unanimously overruled a previous order by a Florida judge to appoint a "special master" to review documents seized at his Mar-a-Lago estate in Palm Beach in August, preventing the Justice Department from using them in its investigation of Mr Trump's behaviour in the documents case.

The seized papers include thousands of White House records that were property of the US National Archives, and more than 100 classified documents, some of the marked with the highest secrecy designations.

The appointment of the special master, and related orders by the Florida judge, delayed and threatened to disable the Justice Department's criminal investigation of Mr Trump for unauthorised possession of national defense information, which falls under the Espionage Act, and for obstruction of justice.

Three Atlanta appeals court justices have now said there was nothing illegal about the 8 August search and document seizure, and that the Florida judge had no jurisdiction to place limits on the Justice Department's examination of the documents.

They also rejected Mr Trump's claim that the search and seizure violated his rights and that as a former president, he deserved special treatment to protect his reputation.

"It is indeed extraordinary for a warrant to be executed at the home of a former president but not in a way that affects our legal analysis or otherwise gives the judiciary licence to interfere in an ongoing investigation," the justices wrote.

The ruling effectively removes restrictions that could have hampered the investigation by Special Counsel Jack Smith, who was appointed two weeks ago to take charge of the two major federal investigations.

One of those is of Mr Trump's role in the 6 January 2021 assault by his supporters on the US Capitol, and the second is of his alleged mishandling of the Mar-a-Lago documents.

Attorney General Merrick Garland named Mr Smith as an independent investigator in an effort to fend off allegations of a politicised investigation after Mr Trump announced he would run for president again in 2024.