WASHINGTON (AFP) - A US judge refused on Saturday (June 20) to block the release of a tell-all book in which President Donald Trump's former national security adviser describes him as corrupt and incompetent.

With John Bolton's book already widely shipped to stores for sale next week, Judge Royce Lamberth wrote that it is too late for a restraining order sought by the Trump administration to halt the process.

The DC district court judge said Bolton appeared to have failed to get written White House agreement that his memoir contained nothing classified, but still refused to hold up the memoir.

"While Bolton's unilateral conduct raises grave national security concerns, the government has not established that an injunction is an appropriate remedy," the judge wrote.

The judge said a review of passages that the government contends contain classified material had persuaded him that Bolton "likely jeopardised national security through publication."

Despite failing to have the book halted, Trump quickly took to Twitter to hail a "big court win" against Bolton.

"Obviously, with the book already given out and leaked to many people and the media, nothing the highly respected Judge could have done about stopping it...BUT, strong & powerful statements & rulings on MONEY & on BREAKING CLASSIFICATION were made.

"Bolton broke the law and has been called out and rebuked for so doing, with a really big price to pay."

Bolton's attorney, Charles Cooper, welcomed the judge's ruling but disputed the finding that Bolton did not fully comply with his vetting obligation.

"The case will now proceed to development of the full record on that issue. The full story of these events has yet to be told - but it will be," Cooper said in a statement.

The book, entitled The Room Where It Happened, has been widely shipped ahead of its Tuesday publication date and many of its most damning allegations against Trump have already been reported in the media.

It is Bolton's portrait of 17 months up close with Trump, until he was fired in September, although Trump characterises the work as "fiction."

Bolton, a lifelong Republican who stands firmly on the right of the party, contends that Trump is not "fit for office."

He describes Trump "pleading" with Chinese President Xi Jinping during trade negotiations to boost the US president's chances of re-election in November by buying more farm products to help agricultural states.

Bolton also reports that Trump, a real estate tycoon who never held office before winning the White House, thought Finland was part of Russia.

'UKRAINE-LIKE TRANSGRESSIONS'

Bolton also backs up the allegations at the center of Trump's impeachment last year that he pressured Ukraine to dig up dirt to weaken his Democratic presidential rival Joe Biden.

Not only this, but Trump committed other "Ukraine-like transgressions" in his wielding of foreign policy for personal gain, Bolton alleges.

The sensationally blunt appraisal from someone who had such high-level access has rocked the White House, with the president already mired in criticism over his handling of the coronavirus pandemic and racial tensions.

Deputy assistant attorney-general David Morrell said Bolton had agreed not to publish a book with classified information "without written authorisation."

"In exchange for money, he has broken that promise," Morrell said. "He should not be rewarded."

The backlash over the book from Trump loyalists and the president himself has been savage.

Trump has called Bolton "a sick puppy," a "boring fool" and a "washed-up guy."

Secretary of State Mike Pompeo branded Bolton a traitor.

"John Bolton is spreading a number of lies, fully-spun half-truths and outright falsehoods," Pompeo said in a statement.