A United States federal judge has granted former president Donald Trump’s request for a special master to review documents seized from his Florida home by the FBI and temporarily stopped the Justice Department using the records in its investigation.

In a decision handed down on Monday, District Judge Aileen Cannon authorised an outside legal expert to review the records taken during the August 8 search and weed out any protected by claims of attorney-client privilege or executive privilege from the rest of the investigation.

The judge put off a ruling on whether some of the records may ultimately be returned to Mr Trump.

The order came despite strenuous objections from the Justice Department, which said a special master was not needed because officials had completed their review of potentially privileged documents.

Justice Department spokesman Anthony Coley said it would review the decision but did not indicate if and when it might appeal.

The order will slow the pace of the investigation into the presence of top-secret information at Mar-a-Lago, particularly given the judge’s directive the Justice Department may not for the moment use any of the seized materials as part of its investigation into the storage of government secrets at the Florida property.

The injunction is in place until the yet-to-be-named special master completes his or her work, or until “further court order”.

“The Court is mindful that restraints on criminal prosecutions are disfavoured, but finds that these unprecedented circumstances call for a brief pause to allow for neutral, third-party review to ensure a just process with adequate safeguards,” Judge Cannon, a Trump appointee, wrote in her 24-page order.

It is not clear if the decision will impede the investigation’s progress or significantly affect the outcome.

Separate assessment by the US intelligence community of the risk posed by the apparent mishandling of classified records will continue under the judge’s order.

The department and Mr Trump’s lawyers will submit a list of proposed special master candidates by Friday.

While the decision is a victory for Mr Trump, it is by no means “an overwhelming win”, Florida criminal defence lawyer and former Justice Department prosecutor David Weinstein said in an email.

“While it is a setback for the government, it is also not a devastating loss for them,” he said.

– AAP