An explosive account of former prime minister Tony Abbott's downfall, including concerns about an affair and details of Bronwyn Bishop's helicopter apology, is set to hit bookstores.
Niki Savva's The Road to Ruin will be released on Monday, with excerpts from the book already grabbing headlines.
Ms Savva has revealed it was Mr Abbott's office that instructed former speaker Bronwyn Bishop not to apologise for the $5000 helicopter ride she charged to taxpayers because it would imply guilt.
That's despite Mrs Bishop wanting to lay it all on the line and say sorry once the details were spread all over the newspapers.
The ordeal over the expensive ride to a Liberal Party fundraiser sparked community anger and lost Mrs Bishop the speakership.
The revelation followed details of Liberal senator Concetta Fierravanti-Wells' concern about a rumoured affair between Mr Abbott and his former chief of staff Peta Credlin.
Senator Fierravanti-Wells told Mr Abbott in February 2015 - on the eve of a leadership spill vote - that the perception he was having an affair with Ms Credlin was damaging him.
Ms Savva says Ms Credlin believed she controlled the former prime minister and could get him to do whatever she wanted.
Coalition MPs have played down the accounts in Ms Savva's book, with Attorney-General George Brandis saying the events should be left to historians.
But Communications Minister Mitch Fifield has urged his coalition colleagues to take it in their stride, saying it was right for history to be recorded.
