Donald Trump, the former US president and leading contender for the 2024 Republican ticket, has refused to testify again at his civil fraud trial in New York, claiming he has “nothing more to add”.

Trump, who gave a “very successful & conclusive” testimony last month, according to his own words, said on Sunday that he had no reason to repeat himself. “I have already testified to everything & have nothing more to add,” Trump wrote on his Truth Social platform.

Trump was due to face the court on Monday over accusations that he, his relatives and staff boosted the value of their real estate holdings by billions of dollars to secure better terms for loans and insurance.

His lawyer, Christopher Kise, said there was “really nothing more to add to a judge who has imposed an unconstitutional gag order and thus far appears to have ignored President Trump’s testimony and that of everyone else involved in the complex financial transactions at issue in the case”.

The lawsuit, filed by New York Attorney General Letitia James, alleges that Trump “committed years of financial fraud and unjustly enriched himself and his family”. “No matter how much he tries to distract from reality, the facts don’t lie,” James said. On November 6, Trump gave a defiant and confrontational testimony for over three and a half hours, in which he denied any wrongdoing and defended his wealth.

Judge Arthur Engoron has already found that James’s office has presented “conclusive evidence” that Trump inflated his net worth by between $812m and $2.2bn and ordered the dissolution of several firms managing the disputed assets. Engoron, who Trump has called “hostile” and a “political hack”, fined the former president $15,000 in October for breaching a partial gag order over insulting comments he made about the judge’s law clerk.

Trump has dismissed the trial, which does not entail any criminal sanctions such as jail time, as a partisan “witch hunt”. The trial will go on without Trump’s testimony and is expected to end in January.