NEW YORK (Reuters) -Donald Trump's lawyers on Wednesday urged a New York judge to declare a mistrial in a civil fraud case over his family real estate company's business practices, but the former U.S. president faces long odds of getting a new trial.

Lawyers for Trump and his family company argued in court filings that the conduct of Justice Arthur Engoron, who is overseeing the case, and his law clerk led to questions about the case's fairness.

Alina Habba, one of Trump's lawyers, said in court after Trump testified earlier this month that the defense planned to move for a mistrial. She said the motion may need to reference materials covered under a gag order imposed by Justice Arthur Engoron on Nov. 4, such as the judge's communications with his staff.

Engoron first imposed a gag order on Oct. 3 after Trump shared on social media a photo of the judge's principal law clerk posing with U.S. Senate Majority leader Chuck Schumer, a Democrat, and falsely called her Schumer's "girlfriend."

The expanded gag order covers lawyers as well after a member of Trump's legal team, Christopher Kise, objected to the clerk passing notes to the judge during the trial. Defense lawyers in the case have suggested the clerk was biased.

It is highly unlikely that Engoron will declare a mistrial, given his earlier fraud findings and defense of his law clerk's conduct.

It also isn't clear when the case could be retried, given that Trump is a defendant in five other criminal and civil cases that could or will go to trial starting in January. Trump, the frontrunner for the 2024 Republican nomination for the U.S. presidency, has denied wrongdoing in all those cases.

The lawsuit over his real estate practices, brought by Democratic New York state Attorney General Letitia James, accuses Trump pumping up the value of apartment towers, golf courses and other assets to win better financing terms.

Engoron has already found Trump, his adult sons and 10 of his companies liable for fraud, describing in scathing terms how the defendants made up valuations. Engoron's ruling could strip Trump's control of some of his best known properties, though that order is on hold during appeal.

Trump on the stand defended his business practices and called the case "election interference."

(Reporting by Luc Cohen in New York)