A New York grand jury will not meet after all Wednesday, US media reported, delaying a decision on whether to charge ex-president Donald Trump over hush money paid to a porn star.

The panel, which operates in secret, usually gathers on Monday, Wednesday and Thursday afternoons, leading to speculation that a vote on a historic indictment of a former president was imminent.

Wednesday's session was called off, however, unnamed law enforcement officials told multiple US outlets without giving a reason for the pause. The New York Times reported that interruptions in grand jury proceedings are not unusual.

Insider, which broke the news of the canceled meeting, quoted one source as saying the panel may not gather again this week, meaning that the earliest a decision might come is Monday.

With barricades outside Trump Tower and police on high alert, New York has been holding its breath over the expected indictment for days, particularly after Trump claimed at the weekend that he would be arrested on Tuesday. He wasn't.

The 76-year-old Republican would become the first former or sitting president to ever be charged with a crime if the panel votes to indict.

The unprecedented move would send shockwaves through the 2024 election campaign, in which Trump is running to regain office.

It would also raise the prospect of a former leader of the free world being arrested, booked, fingerprinted and possibly handcuffed.

Manhattan District Attorney Alvin Bragg formed the grand jury in January following his investigation into $130,000 paid to Stormy Daniels in 2016.

Grand juries operate behind closed doors to prevent perjury or witness tampering before trials, making it virtually impossible to follow their proceedings.

A spokesperson for Bragg told AFP that she "can't confirm or comment on grand jury matters."

Even once the panel takes a decision, it is unclear when Bragg would announce any charges.

Legal experts have suggested it could take some time before Trump -- currently at his Mar-a-Lago resort in Florida -- is arraigned before a Manhattan Criminal Court judge.

The hush-money payment was made weeks before the 2016 election, allegedly to stop Daniels from going public about a liaison she says she had with Trump years earlier.

Trump denies the affair and has called the inquiry a "witch hunt."

Trump calls for protests

His ex-lawyer-turned-adversary Michael Cohen, who has testified before the grand jury, told Congress in 2019 that he made the payment on Trump's behalf and was later reimbursed.

The payment to Daniels, if not properly accounted for, could result in a misdemeanor charge for falsifying business records, experts say.

That might be raised to a felony if the false accounting was intended to cover up a second crime, such as a campaign finance violation, which is punishable by up to four years behind bars.

Analysts say that argument is untested and would be difficult to prove in court, and any jail time is far from certain.

An indictment would begin a lengthy process that could last several months, if not more. The case would face a mountain of legal issues as it moves toward jury selection and pose a security headache for Secret Service agents who protect Trump.

Trump has called for massive demonstrations if he is charged, fueling fears of unrest similar to the January 6, 2021 riot at the US Capitol, but so far protests have been small and muted.

New York police have erected barricades outside the courthouse and Trump Tower.

Trump is facing several criminal investigations at the state and federal level over possible wrongdoing that threaten his new run at the White House, many more serious than the Manhattan case.

They include his efforts to overturn his 2020 election loss in the state of Georgia, his handling of classified documents, and his possible involvement in the January 6 rioting.

Some observers believe an indictment bodes ill for Trump's 2024 chances, while others say it could boost his support.