Donald Trump made his name and fortune in New York, but supporters of the former president are thin on the ground in the city that never sleeps ahead of his historic trial that opens Monday.

"He has to face justice, right?" said Valmir Do Carmo, 30, a babysitter, as he walked his dogs on Court Street in the city's Brooklyn borough.

"He hasn't a lot of supporters in New York City though, but I'm confident, New York City... is very upfront, and I'm pretty sure justice is going to be made."

Trump has repeatedly claimed that he will be unable to get a fair trial in New York which leans Democratic in local and national elections, and because of the intense media scrutiny his cases have attracted.

Comic Stephen Colbert, who shoots his late night TV show in the city, joked this week that Trump was seeking "an impartial jury who knew nothing about the events in America over the last nine years."

"I don't know if he'll get a fair trial, but whatever happens, he caused it on himself. Because everything he does, he likes to put it on the news or TV," said carer Alberto Vasquez, 45.

"Whether it's good or bad, he likes to get a lot of attention. So he did it to himself. Whatever the outcome is, he did it to himself."

Trump's past judicial appearances in New York have sparked spirited protests.

Demonstrators brandishing placards emblazoned with the words "lock him up!" have faced off against pro-Trump supporters, separated by large numbers of armed police.

New York's police department has promised a major deployment to ensure the trial passes off safely, with the force's head of intelligence John Hart calling it a "major challenge."

"New Yorkers are tough and we are not scared," said dog trainer Lee Cahill-Trebing, 36, on the prospect of Trump backers seeking to intimidate those opposed to the former president.

"We will not be bullied out of taking him out of power or upholding the law. So yeah, bring it."

If convicted, Trump faces up to four years in jail on each of the 34 counts of falsifying business records.

He is accused over an alleged scheme to cover up an alleged sexual encounter with porn star Stormy Daniels so as not to doom his 2016 election.

The judge in the case, Juan Merchan, will begin to assemble a jury of 12 New Yorkers, with both the prosecution and defense able to challenge the panelists on impartiality grounds.

But not all New Yorkers are excited about the prospect of the former president, who made his name as a property developer and reality TV star in the city, potentially being jailed.

"I don't really think he should go to prison," said retiree Porter Bell, 83. "I think right now this country is just too divided."

Trump is no stranger to courtrooms in the city after his civil fraud trial which saw him handed a $355 million penalty -- which he is appealing -- and during his sex assault defamation case that saw a jury order him to pay $83 million.