US President Donald Trump said he kept former White House aide Omarosa Manigault Newman on staff because she praised him. Picture: AP Photo/Evan Vucci, File

Washington - US President Donald Trump on Monday said he kept former White House aide Omarosa Manigault Newman on staff because she praised him even as she failed to do her job, the latest insult in the two former reality television stars' public battle.

Trump said the former "The Apprentice" contestant had begged for a job in the White House but was hated by others, missed work and was "nasty." Still, he said he directed his chief of staff, John Kelly, to try to smooth things over with her.

"When Gen. Kelly came on board he told me she was a loser & nothing but problems. I told him to try working it out, if possible, because she only said GREAT things about me - until she got fired!" he wrote in a series of posts on Twitter.

Ahead of the Tuesday release of her book "Unhinged," which describes her time in the White House, Omarosa - known commonly by her first name - has released recordings of conversations she had with Kelly and Trump when she was fired in December.

The White House has pushed back, saying the recordings raise questions about her integrity. Spokeswoman Sarah Sanders on Sunday also said the recordings, including one in the White House's secure Situation Room, showed "a blatant disregard for our national security."

Asked if she was concerned about any legal consequences, Omarosa told NBC's "Today" programme: "No, absolutely not."

She was previously best known for repeatedly being fired on NBC's "The Apprentice" and was one of Trump's more visible African-American supporters during his 2016 election campaign.

"It's sad that with all the things that's going on in the country that he would take time out to insult me and to insult my intelligence," she told MSNBC in reaction to Trump's tweets. "This is his pattern with African-Americans, and he doesn't know how to control himself."