Jurors in the historic trial also heard briefly on Monday from the prosecution's first witness: former National Enquirer publisher David Pecker, who prosecutors say participated in a "catch and kill" scheme to suppress unflattering stories about Trump and help him get elected.
In the first-ever trial of a former US president, Trump is charged with falsifying business records to cover up a $US130,000 ($A202,000) payment to porn star Stormy Daniels in 2016 to keep quiet about a sexual encounter she says they had 10 years earlier. Trump has pleaded not guilty and denies the encounter took place.
Donald Trump is accused of covering up a hush money payment to porn star Stormy Daniels. (AP PHOTO)
Prosecutors portrayed the payment as a criminal effort to deceive voters at a time when Trump was facing other accusations of crude sexual behaviour.
"This was a planned, coordinated, long-running conspiracy to influence the 2016 election, to help Donald Trump get elected through illegal expenditures to silence people who had something bad to say about his behaviour," prosecutor Matthew Colangelo said.
"It was election fraud, pure and simple."
Wearing a blue tie and dark blue suit, the Republican presidential candidate watched the court proceedings and occasionally spoke to his lawyer. A Secret Service agent wearing an earpiece sat directly behind him.
The lawyers made their opening statements in what may be the only one of Trump's four criminal prosecutions to go to trial before his November 5 election rematch with Democratic President Joe Biden.
The case is seen by many legal experts as the least consequential of the Trump prosecutions, based on facts that have been public since 2018. A guilty verdict would not bar him from taking office, but it could hurt his candidacy.
Reuters/Ipsos polling shows half of independent voters and one in four Republicans say they would not vote for Trump if he is convicted of a crime.
This may be the only one of Donald Trump's four criminal cases to go to trial before the election (AP PHOTO)
Before proceedings got under way, Trump called on his supporters to peacefully protest nationwide, but few greeted him when he arrived at the downtown Manhattan courthouse. Trump blamed security restrictions for the poor turnout, though the surrounding streets were open to the public.
Trump faces three other criminal indictments stemming from his efforts to overturn his 2020 election defeat and his handling of classified documents after leaving the White House in 2021.
Trump has pleaded not guilty in those cases, and he portrays all of them as a broad-based effort by Biden's Democratic allies to undercut his campaign.
With the 2024 election campaign in full swing, Trump now must juggle courtroom appearances and rallies.
Trump has pleaded not guilty to 34 counts of falsifying business records. Prosecutors say he falsified checks and invoices to disguise $US420,000 ($A652,000) in payments to his personal lawyer Michael Cohen as legal services, when in fact they were meant to reimburse him for paying off Daniels.
Colangelo said those payments were part of a broader pattern by Trump, Cohen and Pecker to tamp down other unflattering stories and help him defeat Democrat Hillary Clinton.
Trump is facing 34 felony counts of falsifying records related to payments made to a porn star. (EPA PHOTO)
According to prosecutors, Pecker agreed during an August 2015 meeting with Trump and Cohen to act as the campaign's "eyes and ears" by looking out for negative stories about Trump.
"Pecker was not acting as a publisher, he was acting as a co-conspirator," Colangelo said.
Pecker has not been charged with a crime.
Cohen's credibility as a witness is likely to be a crucial aspect of the trial, which could last six to eight weeks. He has pleaded guilty and served prison time on federal campaign-finance charges related to his role in the scheme.
