The author of a book that is highly critical of Donald Trump's first year as US President said his revelations were likely to bring an end to Trump's time in the White House.

Michael Wolff told BBC radio that his conclusion in Fire and Fury: Inside the Trump White House that Trump is not fit to do the job was becoming a widespread view.

'I think one of the interesting effects of the book so far is a very clear emperor-has-no-clothes effect,' Wolff said in an interview broadcast on Saturday.

'The story that I have told seems to present this presidency in such a way that it says he can't do his job,' Wolff said. 'Suddenly everywhere people are going, "Oh my God, it's true, he has no clothes." That's the background to the perception and the understanding that will finally end...this presidency.'

Trump has dismissed the book as full of lies. It depicts a chaotic White House, a president who was ill-prepared to win the office in 2016, and Trump aides who scorned his abilities.

Lawyers for Trump had called on the book's publisher, Henry Holt & Co, to halt the book's release, originally scheduled for Tuesday. Instead, it began sales early and on Friday, its first day in stores, Fire and Fury was the top-selling book on Amazon.com.

In Washington, customers lined up in bitterly cold weather to purchase a copy at KramerBooks, which began selling copies at midnight. Many Washington-area bookstores, including KramerBooks, reported selling out of copies as of Friday morning at 10 am ET (1500 GMT).