Former president Donald Trump has been invited to testify before a New York grand jury investigating hush money payments made on his behalf during his 2016 presidential campaign, according to one of his lawyers.

Trump attorney Joseph Tacopina confirmed on Thursday the Manhattan district attorney's office has invited the former president to testify next week as prosecutors near a decision on whether to proceed with what could be the first criminal case ever brought against a former United States president.

"To me, it's much ado about nothing," Tacopina told the Associated Press, adding he didn't think prosecutors had committed "one way or another" on a decision on whether to charge Trump.

He said there was no legal basis for a case.

"It's just another example of them weaponising the justice system against him. And it's sort of unfair," he said.

The office of Manhattan District Attorney Alvin Bragg, a Democrat, declined to comment.

Such an invitation to testify before a grand jury often indicates a decision on indictments is near.

The invitation to testify was first reported by The New York Times.

Any indictment would come as Trump is ramping up a run to regain the White House in 2024 while simultaneously battling legal problems on multiple fronts.

Trump, in a lengthy statement posted on his social media network, blasted the investigation as a "political Witch-Hunt trying to take down the leading candidate, by far, in the Republican Party" and what he called a "corrupt, depraved, and weaponised justice system".

"I did absolutely nothing wrong," he said.

Meanwhile, the district attorney in Atlanta, Georgia, has said decisions are "imminent" in a two-year investigation into possible illegal meddling in the 2020 election by Trump and his allies.

A US Justice Department special counsel is also investigating efforts by Trump and his allies to undo the election as well as the handling of classified documents at his Florida estate.

The New York grand jury has been probing Trump's involvement in a $US130,000 ($A196,489) payment made in 2016 to the porn star Stormy Daniels to keep her from going public about a sexual encounter she said she had with the Republican years earlier.

The money was paid out of the personal funds of Trump's now-estranged lawyer, Michael Cohen, who then said he was reimbursed by the Trump Organization and also paid extra bonuses for a total that eventually rose to $US420,000 ($A634,809).

Cohen pleaded guilty to federal charges in 2018 that the payment, and another he helped arrange to the model Karen McDougal through the parent company of the National Enquirer tabloid, amounted to an illegal campaign contribution.

Federal prosecutors at the time decided not to bring charges against Trump, who by then was president.

The Manhattan district attorney's office then launched its own investigation, which lingered for several years but has gathered momentum in recent weeks.

Separately, the district attorney's office has also spent years investigating whether Trump and his company inflated the value of some its assets in dealings with lenders and potential business partners.

Those allegations are the subject of a civil lawsuit, filed by the state's attorney general.