Former Australian Prime Minister Tony Abbott allegedly gave his chief of staff Peta Credlin "a slap on the bum" causing her to smile, without realising a Liberal MP had witnessed it, a new book has revealed.

Political commentator Niki Savva has penned a book titled The Road to Ruin, detailing the bizarre relationship between Mr Abbott and Ms Credlin, including their rumoured affair.

Mr Abbott and Ms Credlin have denied any romantic involvement.

"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," Senator Concetta Fierravanti-Wells told Mr Abbott, according to the book.


It says Mr Abbott responded calmly and said the rumours were not true.

Senator Fierravanti-Wells reportedly told Mr Abbott in February 2015 - on the eve of a leadership spill vote - that the perception of the affair was damaging him.

Ms Savva said confronting the pair took a "fair bit of courage".

"It wasn't just those rumours, it was everything else to do with their behaviour," she said.

"Their behaviour, the way they ran the office, the way they ran the Government, ultimately led to their downfall.

"Whatever she [Ms Credlin] thought should happen, she could get him to do and he was completely bound to her."

A number of former staff told Ms Savva they were concerned after Mr Abbott's wife, Margie, was taken off the guest list for an election party under Ms Credlin's orders, The Herald Sun reported.

"People in the inner circle reported that it was rare or exceptional for Credlin and Margie to be in the same room or at the same event together."

The book also reports Mr Abbott was seen by a Liberal MP giving Ms Credlin a 'slap on the bum', and the pair are said to have had matching campaign luggage.

It also reveals Mr Abbott asked one of his colleagues to apologise to his Ms Credlin after he asked her to refrain from swearing at junior members of the party.

The book recounts warnings to Mr Abbott that he would lose the prime ministership unless he dumped Ms Credlin. That never happened and he was toppled by Malcolm Turnbull.

Approached by reporters on Saturday, Mr Abbott refused to comment.

Frontbencher Christopher Pyne said this new book was the big news of the morning.

"I have to say I thought it was a bit of a fizzer to be honest. It was certainly pretty benign," he told Sky News.

"If that's all that Niki Savva has in her book, I don't think that's going to cause too many ripples. There wasn't anything particularly new in it."

The book also claims Bronwyn Bishop was instructed by Tony Abbott's office not to apologise for the $5000 helicopter ride that cost the former speaker her job.

According to the book, Mrs Bishop wanted to "lay it all on the line" and issue a "grovelling" apology for taking the expensive ride at the taxpayers expense.

But the former prime minister's office told her not to say sorry because it would imply guilt and could spark a domino effect that would impact on others.

Mrs Bishop's lack of apology sparked community anger, and almost three weeks after the trip was aired publicly, she lost the speakership.

- Daily Mail