Former prime minister Tony Abbott has declined to comment on a new book charting the demise of his government, including revelations he was told to dump his chief of staff Peta Credlin, partly because of a "perception" they were having an affair.

Key points: A new book includes revelations about Mr Abbott and chief of staff Peta Credlin

A new book includes revelations about Mr Abbott and chief of staff Peta Credlin It includes accounts from politicians saying Abbott should sack Credlin

It includes accounts from politicians saying Abbott should sack Credlin Senator Fierraventi-Wells said there were rumours Abbott and Credlin were sleeping together

Senator Fierraventi-Wells said there were rumours Abbott and Credlin were sleeping together Abbott refuses to comment, saying he "won't rake over old coals"

That warning came from senior Liberal Senator Concetta Fierravanti-Wells who has confirmed she confronted both Mr Abbott and Ms Credlin about rumours circulating among colleagues that he was "sleeping with her". Both denied the affair.

Ms Fierraventi-Wells is one of several senior government figures who have come forward to give on-the-record accounts which have been published in a book by Niki Savva called The Road to Ruin: How Tony Abbott and Peta Credlin destroyed their own government.

The book focuses on the insular relationship between the pair, and the influence and power Ms Credlin had within Mr Abbott's office.

According to an extract published in The Australian, Senator Fierravanti-Wells went to Mr Abbott the night before the failed first attempt to unseat him last February.

She told the then-prime minister he had to remove Ms Credlin, arguing colleagues considered her responsible for many of the government's problems, and they were prepared to take out their frustrations on him.

Senator Fierravanti-Wells is quoted in the book as telling Mr Abbott "politics is about perceptions".

"Rightly or wrongly, the perception is that you are sleeping with your chief of staff. That's the perception, and you need to deal with it.

"I am here because I care about you, and I care about your family, and I feel I need to tell you the truth, the brutal truth. This is what your colleagues really think."

According to the book, Mr Abbott responded calmly and said the rumours were not true.

Mr Abbott was not ousted in that February motion, but the chain of events was considered a precursor to his ultimate downfall in September.

According to the book, Senator Fierravanti-Wells also put the rumours directly to Ms Credlin a few days after the February motion.

Ms Credlin also denied it, and the recollection is that she said she would not leave Mr Abbott's office, arguing he would not be able to do his job as prime minister without her.

"One day, Tony will be sitting on a park bench in Manly feeding the pigeons, and he will blame you," Senator Fierravanti-Wells replied, according to the book.

Senator Fierravanti-Wells has told the ABC the account is accurate but Mr Abbott has declined to comment.

"I'm not going to rake over old coals, I'm not going to dwell on the past," he said.

Sorry, this video has expired Tony Abbott won't 'dwell on the past'

Credlin thought Abbott was incapable without her: Laurie Oakes

Channel Nine senior political journalist Laurie Oakes has also had access to the book ahead of its publication on Monday, and said Ms Credlin's comment showed she thought Mr Abbott was incapable of doing his job without her.

According to Oakes, the book includes a quote — with the approval of a senior government adviser — that says: "He [Abbott] knew he wasn't up to it, she knew he wasn't up to it, so they both hunkered down."

Oakes has written about another anecdote from the book provided by a Liberal MP.

The MP recalled being invited to dine with Mr Abbott and Ms Credlin and watched Ms Credlin use her fork to feed Mr Abbott mouthfuls of food from her plate.

As the meal was ending the MP recalled Ms Credlin put her head on Mr Abbott's shoulder and said she was tired.

Abbott says he is committed to re-election of Turnbull

The book comes as tensions resurface between Mr Abbott and the man who replaced him, Malcolm Turnbull, following last September's leadership spill.

Mr Abbott's interventions in the tax debate and future submarine project incensed some of his colleagues who believe he is undermining the Prime Minister and destabilising the Government.

But Mr Abbott said he was fully committed to the re-election of the Turnbull Government.

"They know me, my colleagues have known me for 22 years," he said.

"They know that I have an absolutely profound commitment to our party and a profound commitment to the well being of this country, that's the way I've always been."