A federal judge in Florida has ordered the US Justice Department to make public a redacted version of an affidavit underpinning the FBI search of former president Donald Trump’s Florida home.

The move will possibly provide fresh insights into the investigation and evidence earlier obtained by the government.

US Magistrate Judge Bruce Reinhart ordered the redacted document to be released by noon on Friday (0200 AEST on Saturday).

His order on Thursday (local time) came just hours after a Justice Department spokesman confirmed that prosecutors had submitted a sealed copy of the affidavit with proposed redactions to the judge.

Judge Reinhart approved the Justice Department’s warrant that preceded the FBI search of Mr Trump’s Mar-a-Lago residence in Palm Beach.

The affidavit is a sworn statement outlining the evidence that gave the department probable cause to seek a search warrant.

Just how much the redacted affidavit will reveal remains to be seen.

In his order on Thursday, Judge Reinhart said the Justice Department had valid reasons to keep some of the document secret, including the need to protect the identities of witnesses and federal agents, as well as the government’s investigation and strategy and grand jury material.

The FBI in its court-approved search at Mar-a-Lago on August 8 seized more than 20 boxes containing 11 sets of classified government records, some labelled “top secret”.

The search was part of a federal investigation into whether Mr Trump illegally removed and kept documents from the White House when he left office in January 2021 and whether he tried to obstruct the government’s investigation.

After Mr Trump accused the FBI of political retribution against him, Attorney-General Merrick Garland made the unusual decision to confirm the existence of the department’s investigation and asked a court to unseal large portions of the search warrant and property receipt listing the seized items.

The department declined to release the affidavit, prompting media companies to file a legal challenge to get it unsealed.

At a hearing last week, prosecutors asked Judge Reinhart not to release the document, saying it could harm their ongoing investigation and chill witness co-operation as well as create security risks for FBI agents already facing heightened threats.

Mr Trump on social media called for the document to be unsealed, though his lawyers had not weighed in on the matter.

-AAP