Former US president Donald Trump expects to be arrested on Tuesday as New York prosecutors consider charges over a hush money payment to a porn star, and called on his supporters to protest.

“Illegal leaks from a corrupt & highly political Manhattan district attorney’s office … indicate that, with no crime being able to be proven … the far & away leading Republican candidate & former president of the United States of America, will be arrested on Tuesday of next week,” Trump wrote on Truth Social on Saturday.

A Trump spokesman said the former president had not been notified of any arrest. Trump provided no evidence for his leaks claim and did not discuss the possible charges in his post.

“Protest, take our nation back!” said Trump, whose supporters stormed the US Capitol building on January 6, 2021, to try to overturn his 2020 presidential election defeat.

The probe comes as Trump seeks the Republican nomination for the presidency in 2024.

No US president – while in office or afterward – has faced criminal charges. Trump has said he will continue campaigning even if he is charged with a crime.

A representative for Manhattan District Attorney Alvin Bragg, whose office has been investigating a $US130,000 ($A194,000) hush payment Trump’s former personal lawyer Michael Cohen made to porn actor Stormy Daniels, declined to comment.

Sources have said Bragg’s office has been presenting evidence to a grand jury about the payment, which came in the waning days of Trump’s 2016 campaign in exchange for Daniels’ silence about an affair she said she had with Trump a decade earlier.

Trump has denied the affair happened and called the investigation by Bragg, a Democrat, a witch hunt.

Trump’s statement that he expected to be arrested on Tuesday was based on news reports that Bragg’s office was going to meet law enforcement to prepare for a possible indictment, a person familiar with the matter said.

The Republican speaker of the US House of Representatives, Kevin McCarthy, decried the investigation.

“Here we go again – an outrageous abuse of power by a radical DA who lets violent criminals walk as he pursues political vengeance against President Trump,” McCarthy said on Twitter.

McCarthy’s predecessor as speaker, Democratic Representative Nancy Pelosi, who like McCarthy was present at the Capitol when hundreds of Trump supporters stormed the building, battling with police, denounced Trump’s call.

“The former president’s announcement this morning is reckless: doing so to keep himself in the news and to foment unrest among his supporters,” Pelosi said in a statement.

“He cannot hide from his violations of the law, disrespect for our elections and incitements to violence.”

Bragg’s office this month invited Trump to testify before the grand jury probing the payment, which legal experts said was a sign that an indictment was close. Trump declined the offer.

Cohen pleaded guilty in 2018 to federal campaign finance violations tied to his arranging payments to Daniels and another woman in exchange for their silence about affairs they said they’d had with Trump, among other crimes.

He has said Trump directed him to make the payments. The US Attorney’s office in Manhattan did not charge Trump with a crime.

The probe is one of several legal woes Trump faces as he seeks the Republican nomination for the presidency.

Trump is also confronting a state-level criminal probe in Georgia over efforts to overturn the 2020 results in that state.

A special counsel named by US Attorney General Merrick Garland is investigating Trump’s handling of classified government documents after leaving office, as well as his efforts to overturn the results of the 2020 election, which he lost to President Joe Biden, a Democrat.

Bragg’s office last year won the conviction of the Trump Organization on tax fraud charges. But Bragg declined to charge Trump himself with financial crimes related to his business practices, prompting two prosecutors who worked on the probe to resign.

Trump leads his early rivals for his party’s nomination, holding the support of 43 per cent of Republicans in a February Reuters/Ipsos poll, compared with 31 per cent for his nearest rival, Florida Governor Ron DeSantis, who has not yet announced his candidacy.

By Luc Cohen and Karen Freifeld in NEW YORK