Donald Trump has lashed out at the New York judge who ruled he must pay $US354.9 million ($A544.4 million) in penalties for fraudulently overstating his net worth to dupe lenders, telling a campaign rally the decision was an "election interference ploy".
Addressing supporters for the first time since Justice Arthur Engoron on Friday hit him with massive financial penalties, Trump made the unsubstantiated claim that the judge was part of a "left wing" conspiracy aimed at stopping him from becoming president again.
The former Republican president, the frontrunner for his party's White House nomination, told a crowd in Michigan that "these repulsive abuses of power are not just an attack on me, they are an attack on all Americans."
Trump also repeated his lie that his 2020 election defeat to Democratic US President Joe Biden was due to election fraud.
Engoron also banned Trump from serving as an officer or director of any New York corporation for three years.
The judge said of Trump and his co-defendants: "Their complete lack of contrition and remorse borders on pathological."
New York Attorney General Letitia James had accused Trump and his family businesses of overstating his net worth by as much $US3.6 billion ($A5.5 billion) a year over a decade to fool bankers into giving him better loan terms.
Trump spoke shortly after Nikki Haley, his last remaining rival for the Republican presidential nomination, who held an event in South Carolina.
On Saturday morning, Haley wasted no time in going after Trump after Friday's ruling, which handed him another legal setback in a civil case that imperils his real estate empire.
Trump also faces four state and federal criminal trials, including one scheduled to start in New York on March 25, over alleged hush money payments to a porn star.
That means Trump will become the first former US president to stand trial on criminal charges.
Haley frequently says "chaos" follows Trump, and that he can't be an effective president or candidate because of his myriad legal problems.
"He's going to be in court March and April. He's going to be in court May and June. He said himself that he's going to be spending more time in a courtroom than he is on the campaign trail," Haley told Fox News.
Trump is close to clinching the Republican presidential nomination, and the prospect of a likely general election rematch with Biden, after recent nominating contest wins in Iowa, New Hampshire and Nevada.
Before his rally in Michigan, Trump appeared at a convention for sneaker fans in Philadelphia, where he launched his own sneaker brand - gold-topped with American flag logos.
"I've wanted to do this a long time," Trump said, before urging young people to vote.
Haley, who has no clear path to the Republican nomination, has refused to quit.
She is making a potential last stand in her home state of South Carolina, which holds its primary on February 24, where she trails badly in opinion polls behind Trump.
At her rally on Saturday evening, Haley also attacked Trump for his failure to comment on the death of Alexei Navalny, Russia's most prominent opposition leader.
At his Michigan rally, Trump again failed to mention Navalny.
Russia's prison service said that Navalny, 47, died on Friday at the "Polar Wolf" Arctic penal colony.
The West, including Biden, has blamed Russian President Vladimir Putin for the death.
