Donald Trump's defence lawyers rested their case on Tuesday – without the former president following through on a vow to testify – as the judge planned jury deliberations in the historic criminal trial for early next week.

After approximately five weeks, 19 witnesses, reams of documents and sometimes salacious testimony, judgment day in the first ever trial of a former US president was drawing closer.

New York law means the trial has not been shown on television and experts are divided on whether the airing of Trump's dirty laundry is having much of a political impact. However, with a clash against President Joe Biden less than six months away, the looming jury verdict represents a moment of acute peril for the Republican.

Judge Juan Merchan told jurors that closing arguments would take place next Tuesday when each side would make their pitch to the 12 New Yorkers who will ultimately decide Trump's fate.

"I will expect you will begin your deliberations hopefully at some point on Wednesday," Merchan said.

Trump's lawyers have sought to undermine key testimony against the former president, who is accused of illegally covering up hush money paid to a porn star over an alleged encounter that could have derailed his successful 2016 White House bid against Hillary Clinton.

Lawyer Robert Costello was grilled on emails he sent to prosecution star witness Michael Cohen after the FBI raided him in 2018, with Trump's lawyers seeking to undermine Cohen and the prosecution case.

Costello sparred with Merchan on Monday, prompting the magistrate to rebuke him for poor courtroom etiquette. Trump, in one of his regular tirades outside the courtroom, accused Merchan of being a "tyrant" in what he claimed was a "show trial."

Earlier on Monday, both sides asked their final questions of Cohen, Trump's former personal lawyer and ultra-loyal fixer who eventually turned on his boss.

Cohen recounted last week how he kept Trump informed about US$130,000 paid to porn star Stormy Daniels to buy her silence about an alleged affair ahead of the 2016 presidential election.

Trump's lawyers set out to paint Cohen as a convicted criminal and habitual liar, recalling his time in prison for tax fraud and lying to Congress.

Trump lawyer Todd Blanche also probed Cohen's loyalty to Trump and then to the prosecution, looking to show jurors that Cohen is self-serving.

Blanche vied to goad Cohen, who has a reputation for a short temper that could have hurt him on the stand – but the witness largely maintained his composure.

Cohen's story generally lined up with Daniels and David Pecker, the tabloid boss who said he worked with Trump and Cohen to suppress negative coverage during the Republican's 2016 White House run.

After Blanche finished with him, the prosecution returned for redirect, with prosecutor Susan Hoffinger asking Cohen what the whole experience has meant for him.

"My entire life has been turned upside down," Cohen said, emotion in his voice. "I lost my law licence, my financial security..., my family's happiness... just to name a few."

Throughout the trial, which has upended the political and legal order, Trump has complained his 2024 election campaign for another White House term is being stymied by the weeks-long court proceedings, which he has to attend every day.

He did so again on Monday, complaining to journalists he's "not allowed to have anything to do with politics because I'm sitting in a very freezing cold, dark room for the last four weeks. It's very unfair."

Calling the case politicised, a coterie of leading Republicans have stood in the wings behind him as he gives remarks to reporters outside the courtroom.

The growing list includes several lawmakers eyeing Trump's vice presidential pick, including Ohio Senator JD Vance and North Dakota Governor Doug Burgum.

Yet despite the palace intrigue and courtroom drama, the charges ultimately hinge on financial records, and whether falsifying them was done with intent to sway the 2016 presidential vote. (AFP)