A former White House staffer has written a book, in which she claims she witnessed US President Donald Trump being racist "many times".

Omarosa Manigault Newman's title, 'Unhinged: An Insider Account Of The Trump White House', describes Mr Trump as a bigot.

She wrote: "I didn't want to believe it. I rejected what other people said about him because they didn't know him like I did.

"I had to go through the pain of witnessing his racism with my own eyes, and hearing it with my own ears, many times, until I couldn't deny it any longer."

Ms Manigault Newman (44) was a contestant on Mr Trump's reality TV show 'The Apprentice', and later served as senior adviser to the president.

She described him as scattered, self-absorbed, misogynistic and insecure, claimed there are tapes of him using racial slurs while filming 'The Apprentice' and warned that he had shown signs of "mental decline that could not be denied".

Ex-director of communications for the Office of Public Liaison in the White House, Omarosa Manigault | Image: Van Tine Dennis/ABACA/ABACA/PA Images

Ms Manigault Newman added that Mr Trump "loved conflict, chaos and confusion... loved seeing people argue or fight" and had behaved "like a dog off a leash" at events he had attended without his wife.

These included birthdays, fundraisers and golf tournaments.

Ms Manigault Newman also claimed that the president tried to buy her silence when she left the White House in January.

She said she was offered US$15,000 (€13,141) a month to serve in a "senior position" on Mr Trump's 2020 re-election campaign on condition that she signed a "harsh and restrictive" nondisclosure agreement.

After she refused, she said she had received letters from the president's lawyers ordering her to "stay silent about Trump, or else".

The cover of the new book | Image: Amazon

The White House responded angrily to the claims in the book, which is released on August 14th.

Press secretary Sarah Huckabee Sanders said: "Instead of telling the truth about all the good President Trump and his administration are doing to make America safe and prosperous, this book is riddled with lies and false accusations.

"It's sad that a disgruntled former White House employee is trying to profit off these false attacks, and even worse that the media would now give her a platform."