A former employee of Donald Trump is heavily incriminating his former employer in a dispute over government documents confiscated from Trump's private home.

Trump asked him to clear boxes of documents at his home in Florida after the former US President received a request to return the documents, some of which were classified, the Washington Post reported on Wednesday.

The employee, who was employed at Trump's Mar-a-Lago residence, was cooperating with the Justice Department and has been questioned multiple times by federal officials, the newspaper reported, citing people familiar with the matter.

The witness initially denied handling sensitive documents, but later admitted to moving the boxes at Trump's request, the report said.

The testimony of the key witness would be one of the strongest evidence so far of a possible obstruction of justice by the former Republican president.

In early August, the FBI searched Trump's Florida home.

The FBI confiscated various classified documents, some with the highest level of secrecy.

However, a few dozen empty folders with a secret note were also found during the search.

This raised the question of what had happened to the papers originally contained within.

The former Trump employee is now considered a key figure in the investigation into the secret documents, wrote the Washington Post.

Video footage supports his statement that boxes had been moved around, the newspaper reported.

Trump spokesman Taylor Budowich told the Washington Post that the administration of US President Joe Biden is using law enforcement as a weapon against Trump.

"Every other president has been granted time and respect in relation to the management of documents, as the president has ultimate authority to categorize records and decide what materials should be classified," he said.

Budowich accused the Justice Department of providing "misleading and false information" to the media.

The Justice Department said Wednesday that it has turned over most of the documents seized at Donald Trump's Mar-a-Lago estate to the former president's legal team.

This begins a 21-day period during which Trump must decide — and officially state — which records he does not want to use in a criminal investigation.

This could include claims to attorney-client privilege or executive privilege.

By keeping the documents in his private home after Trump left office, he could have made himself liable to prosecution.

After the search, a complicated legal wrangling began, which even the US Supreme Court is now dealing with.

It remains to be seen whether Trump could ultimately be charged.

The 76-year-old Republican has so far left open whether he wants to run for the 2024 presidential election.

Examining the documents is one of several legal issues Trump is facing.

He is considering running for president again in 2024.