Judge tells Trump to amend New York Times lawsuit

A federal judge has thrown out US President Donald Trump's defamation lawsuit against the New York Times over its content, calling it a "decidedly improper and impermissible" effort to attack his adversaries.

US District Judge Steven Merryday said Trump in his $US15 billion ($A23 billion) lawsuit violated a federal civil procedure rule by failing to offer a short and plain statement of why he should prevail over the NYT, four of its reporters and the publisher Penguin Random House.

He faulted the president for instead packing his 85-page complaint with unnecessary statements lauding his successes and "singular brilliance," attacking critics and even defending his father.

"A complaint is not a public forum for vituperation and invective - not a protected platform to rage against an adversary," wrote Merryday, an appointee of Republican former president George HW Bush.

The lawsuit named a book and an article written by reporters that focuses on Trump's finances and his pre-presidency starring role in television's The Apprentice.

The Tampa, Florida-based judge gave Trump 28 days to file an amended complaint "in a professional and dignified manner" of no more than 40 pages.

A spokesman for Trump's legal team said in a statement: "President Trump will continue to hold the Fake News accountable through this powerhouse lawsuit against the New York Times, its reporters and Penguin Random House, in accordance with the judge's direction on logistics."

In a separate statement, a NYT spokesperson said: "We welcome the judge's quick ruling, which recognised that the complaint was a political document rather than a serious legal filing."

Friday's order is an unusual rebuke by a federal judge to a sitting president over decorum in the judicial process.

Trump sued over three articles and a book by two of the NYT reporters.

He accused the defendants of defaming him prior to the 2024 presidential election in order to sabotage his campaign and disparage his reputation as a successful businessman.

In a four-page order, Merryday said plaintiffs like Trump are supposed to "fairly, precisely, directly, soberly and economically" tell defendants in complaints why they are being sued.

Trump's complaint said the defendants "baselessly hate President Trump in a deranged way," and that their actions "represent a new journalistic low for the hopelessly compromised and tarnished 'Grey Lady'," - a nickname for the Times.

It also contended that the NYT itself was "deranged" for endorsing Democrat Kamala Harris for president.

"A complaint is not a megaphone for public relations," the judge wrote.

"Although lawyers receive a modicum of expressive latitude in pleading the claim of a client, the complaint in this action extends far beyond the outer bound of that latitude."

with AP