Donald Trump Jr has testified about what he called the “sexiness” of his father’s real estate portfolio, in his second time being called to the stand in the former US president’s civil fraud trial.

Donald Trump, the frontrunner for the 2024 Republican presidential nomination, is accused along with his two adult sons and 10 of his companies of inflating his net worth by as much as $US2.2 billion ($3.4 billion) to secure better financing.

The lawsuit by New York Attorney General Letitia James seeks at least $US250 million ($392 million) in damages as well as restrictions that would effectively bar Trump and his adult sons from New York’s real estate industry.

In response to questioning from his lawyer Clifford Robert, Donald Jr spoke at length about his father’s business acumen, saying the “sexiness” of his real estate projects attracted licensing deals with other developers who wanted to emulate his style.

Lawyers’ for James’ office objected to the line of questioning as irrelevant, but Justice Arthur Engoron disagreed.

“Let him go ahead and talk about how great the Trump Organisation is,” said Engoron, who has defended himself during the trial from allegations of bias from Trump and his lawyers.

Donald Jr has already been called as a witness by the attorney general’s office, along with his father and brother Eric Trump. His sister Ivanka Trump also testified but is not a defendant.

Trump has denied wrongdoing and accused James, an elected Democrat, of “election interference.”

During defiant and rambling testimony last week, Trump acknowledged inaccuracies on his financial statements but said the discrepancies were not relevant to the banks that used them to price his loans.

Donald Jr, Eric and Ivanka Trump said they were not involved in preparing their father’s financial statements and left bookkeeping at the Trump Organisation to accountants.

The case is largely about damages, as Judge Arthur Engoron has already ruled that Trump and his company fraudulently inflated those asset values.

Engoron has ordered the dissolution of companies that control pillars of Trump’s real estate portfolio, including Trump Tower in Manhattan. That ruling is on hold pending appeal.

Trump faces a maelstrom of legal troubles as he campaigns to challenge Democratic President Joe Biden in the 2024 election, though none have diminished his commanding lead over Republican rivals.

He is a defendant in four criminal trials, including two stemming from his attempts to overturn his 2020 election loss. He has pleaded not guilty in all four cases.

Also on Monday, Trump’s older sister and former federal judge Maryanne Trump Barry died at the age of 86.

Barry died at her home in Manhattan and was found early on Monday morning, the New York Times has reported.

Barry was appointed in 1983 by then-president Ronald Reagan to be a judge in New Jersey’s US District Court and later became a federal appeals court judge. She retired in 2019.

Trump could not be immediately reached for comment.