Special Counsel Robert Mueller has told President Donald Trump’s legal team he would follow Justice Department guidance that a president cannot be indicted, CNN reported, citing an interview with Trump lawyer Rudy Giuliani.

“All they get to do is write a report,” Mr Giuliani, a former New York mayor who joined Mr Trump’s personal legal team in April, was quoted as saying.

“They can’t indict. At least they acknowledged that to us after some battling, they acknowledged that to us.”

A spokesman for Mr Mueller, Peter Carr, did not immediately respond to a Reuters request for comment.

Mr Mueller is investigating allegations that Russia interfered in the 2016 US presidential election and possible collusion between Moscow and the Trump campaign.

CNN said the Mueller team had been debating whether to challenge the Nixon-era guidelines, which were reaffirmed during the Clinton administration, that a sitting president cannot be indicted.

Mr Trump has denied colluding with Russia and has called the Mueller investigation, which marks its first anniversary on Thursday, a witch hunt.

Mr Giuliani and another Trump lawyer, Jay Sekulow, did not immediately respond to a request for comment from Reuters.

Stormy payment details

The claim comes as Mr Trump acknowledged for the first time that he repaid his lawyer Michael Cohen for a payment of at least $US100,001 ($A133,561) made to a “third party” in 2016, according to ethics disclosures signed by the President.

The documents were released by the US Office of Government Ethics on Wednesday. 

Ms Daniels claims of hush money were originally denied by Mr Trump. Photo: Getty

Mr Cohen made a $US130,000 payment to porn star Stormy Daniels, whose real name is Stephanie Clifford, shortly before the November 8, 2016, presidential election in exchange for her staying silent about an alleged affair she had with Mr Trump.

Mr Trump’s new disclosure statement did not describe the purpose or the recipient of the 2016 payment made by Mr Cohen.

But the acting director of the ethics office, David Apol, in a letter to Deputy Attorney General Rod Rosenstein said it should have been disclosed in ethics documents that Mr Trump filed in June 2017.

Mr Apol’s letter was released with the Trump disclosures.

The ethics office is a government watchdog that provides oversight of the executive branch program designed to prevent and resolve conflicts of interest.

Mr Trump’s latest disclosure filing said Mr Cohen incurred the expense in 2016 and that Mr Cohen “sought reimbursement” in 2017. “Mr Trump fully reimbursed Mr Cohen,” the report said.

The payment made by Mr Cohen was between $US100,001 and $US250,000 and there was no interest incurred, the report said.

Mr Trump had previously disputed whether he was aware of the payment by Mr Cohen and if he reimbursed his lawyer.

In April, Mr Trump told reporters he did not know anything about the payment.

On May 2, Mr Giuliani said that Mr Trump had reimbursed Mr Cohen for the payment.

Mr Cohen has publicly acknowledged paying Ms Daniels, saying he obtained the cash through a line of credit on his home.

-with AAP