Trump being Trump, changed his mind about testifying in his defence in his New York fraud case on Monday, he said, announcing that he will not take the stand as expected because he has "nothing more to say."

The 77-year-old posted the surprise statement on Truth Social on Sunday, adding that he has "already testified to everything" in the ongoing trial against him, his eldest sons Don Jr and Eric, and other Trump Organization executives.

Trump was questioned last month by the prosecution, which has accused him and the other defendants of exaggerating the value of their real estate assets by billions of dollars to obtain more favourable bank loans and insurance terms.

For four hours on November 6, Trump sparred with prosecutors, with his acrimonious answers at times earning rebukes from Judge Arthur Engoron, who warned the current Republican front-runner that "this is not a political rally."

On Sunday, Trump said that he had already testified "very successfully & conclusively" in the case.

The Trump real estate empire has been put in jeopardy by the civil suit, brought by New York Attorney General Letitia James and one of a slew of serious legal actions facing Trump ahead of next year's presidential vote.

Even before opening arguments, Engoron ruled that James's office had already shown "conclusive evidence" that Trump had overstated his net worth on financial documents by between $812 million and $2.2 billion between 2014 and 2021.

As a result, the judge ordered the liquidation of the companies managing the assets in question, such as the Trump Tower and 40 Wall Street skyscrapers in Manhattan, a decision currently under appeal.

The trial concerns several other crimes, including insurance fraud, and the financial penalty sought by the Attorney General's office of $250 million.

Unlike some of Trump's legal battles -- including the criminal case against him accusing him of conspiring to overturn the 2020 election -- the suit brought by James, a Democrat, carries no risk of jail time.

Since the start of the trial, which opened October 2, the billionaire Republican has denounced the proceedings as a partisan "witch hunt."