Former presidential adviser and reality TV star Omarosa Manigault Newman says she secretly recorded conversations she had in the White House, including her firing by chief of staff John Kelly in the high-security Situation Room.

The highly unusual admission immediately drew fire from allies of the president and national security experts.

Parts of her conversation with Kelly were played on the air when she appeared on NBC’s Meet the Press on Sunday to promote her new book, Unhinged, which will be released next week.

In her book, Mr Manigault Newman paints a damning picture of President Donald Trump, including claiming that tapes exist of him using the N-word as he filmed his The Apprentice reality series, on which she co-starred.

Ms Manigault Newman said in the book that she had not personally heard the recording.

But she told Chuck Todd on Sunday that, after the book had closed, she was able to hear a recording of Trump during a trip to Los Angeles.

The other recording she discussed on Sunday could prove equally explosive.

“Who in their right mind thinks it’s appropriate to secretly record the White House chief of staff in the Situation Room?” tweeted Ronna McDaniel, chair of the Republican National Committee.

Secretly recording conversations in the Situation Room isn't just wildly inappropriate, it's a threat to our national security. If she broke federal law, she should be prosecuted.

— Ronna McDaniel (@RonnaMcDaniel) August 12, 2018

In the recording, which Ms Manigault Newman quotes extensively in the book, Mr Kelly can be heard saying she can look at her time at the White House as a year of “service to the nation” and referring to potential “difficulty in the future relative to your reputation”.

Ms Manigault Newman said she viewed the comment as a “threat” and defended her decision to covertly record it and other White House conversations, describing it as a form of protection.

“If I didn’t have these recordings, no one in America would believe me,” she said.

The Situation Room is a Sensitive Compartmented Information Facility, or SCIF, and staff are not permitted to bring in mobile phones or other recording devices.

“I’ve never heard of a more serious breach of protocol,” said Ned Price, who served as spokesman of the National Security Council in the Obama administration.

“Not only is it not typical, something like this is unprecedented.”

Mr Price said there is no one checking staffers for devices at the door but there is a sign outside the room making clear that electronic devices are prohibited.

“The Situation Room is the inner-most sanctum of a secure campus,” he said, describing the breach as part of a culture of disregarding security protocols in the Trump White House.

Mr Price also question why Mr Kelly would ever choose to have such a meeting there.

The White House has tried to discredit the book, with Mr Trump on Saturday labelling Ms Manigault Newman a “lowlife”.

White House counsellor Kellyanne Conway also questioned Ms Manigault Newman’s credibility in an interview on Sunday on ABC’s This Week.

“The first time I ever heard Omarosa suggest those awful things about this president are in this book,” she said, noting Ms Manigault Newman “is somebody who gave a glowing appraisal of Donald Trump the businessman, the star of the The Apprentice, the candidate and, indeed, the president of the United States”.

Ms Manigault Newman had indeed been a staunch defender of the President for years, but she now says she was “used” by Mr Trump for years, calling him a “con” who “has been masquerading as someone who is actually open to engaging with diverse communities” and is “truly a racist”.

“I was complicit with this White House deceiving this nation,” she said. “I had a blind spot where it came to Donald Trump.”

-AP