But several of Mr Hockey's Liberal colleagues have criticised the timing and content of the book as “unusual” and “unhelpful” in making the government's case for a budget that broke a series of pre-election promises and delivered deep cuts to health, education and pensions.

On Thursday, Mr Hockey distanced himself from the timing of the publication of Hockey: Not Your Average Joe, written by journalist and broadcaster Madonna King but praised the book for articulating his values.

“I don't agree with every word that has been written in the book but you would not expect me to," he said at the launch of the book.

“Nor did you [Ms King] even broach the subject of me re-writing chapters. I didn't seek to change the book at all because either it is fair dinkum or it's not and it is fair dinkum.

"There are things that I wish were rather not said in the book but they are said, and I in no way apologise for the book.”

In the book, Ms King reports that: “In reality, the budget was much softer than Joe would have liked. He wanted changes to pensions made earlier and the deficit levy to net more taxpayers … But Abbott, who chaired each of the expenditure review committee meetings, was taking a much more cautious approach than his Treasurer, no doubt with one eye firmly on the reaction of voters."

It also quotes Mr Hockey's wife, Melissa Babbage, asserting the Treasurer “won't trust Malcolm again” following the 2009 leadership challenge and reveals a deep-seated enmity with Industry Minister Ian Macfarlane.

But Mr Hockey distanced himself from his wife's comments about Mr Turnbull, declaring “I trust Malcolm Turnbull, yes” and refused to speculate on whether he might be the next leader of the Coalition government.

“We'll leave that to destiny, whatever that may be," he said before adding that suggestions his colleagues were critical of the timing of the book and its contents were “just rumours”.

Mr Abbott's powerful chief of staff, Peta Credlin, also declares in the book Mr Hockey has "got his head above every other contender" to be the next Liberal leader, though she cautions he is not yet the "heir apparent" to replace Mr Abbott.

Mr Hockey also revealed Ms Babbage had initially urged him not to co-operate with Ms King, but after consulting Mr Abbott and others he had decided to do so because it documented his family's immigrant history, of which he was immensely proud.

"There is not a day I don't reflect on the importance of immigration to Australian, including accepting refugees," he said.

"After 18 years of being involved in politics, it is a rewarding experience to know that I have been consistent and true to the values I have held through my life."

Mr Hockey also defended Ms Credlin from criticism for weighing in on the debate about who the next leader of the party would be.

"Peta Credlin is an outstanding individual and if we had three Peta Credlins in federal politics it would raise the level of the quality of public debate,'' he said.

Asked how much tougher he had wanted his first budget to be, Mr Hockey said the balance was "about right".

"The bottom line is, every Treasurer as you would expect would prosecute the case for greater savings or every treasurer worth their salt."

"On the one hand they said Joe didn’t have the ticker to do what needed to be done and when Joe was part of a team that lays down a plan that needs to be done, they say otherwise."

However Liberal Senator Ian Macdonald told Fairfax Media the timing of the book “did seem unusual, though I'm unaware of who makes those decisions and the reasons for it”.

Asked if he believed the budget was too soft, Senator Macdonald said: “There are other measures that could have been taken, in fact I understand that - doctors tell me – there are many obvious ways that the runaway health budget could be brought back into line without the sort of measures contemplated in the budget.”

“Tough decisions had to be made, I accept that. I have for some time now been saying that I thought the pre-release selling of the budget was very poorly done and that I also believe that some of the harsher elements were determined without consultation of the Treasurer and Prime Minister's colleagues, who are at the coalface," he said.

“There are inconsistencies in the budget which are obvious to me and most Australians that don't seem to be as obvious to those who put the budget together.”

Senator Macdonald said the leadership was a “non-issue” in the party room as Mr Abbott had been a “marvellous” opposition leader and prime minister.

A cabinet colleague of Mr Hockey, who asked not to be named, was critical of Ms Credlin's suggestion the Treasurer was in line to be the next leader.

“The leadership of the Liberal Party is decided by the party room," the cabinet minister said.

And a third MP said the book was “really unhelpful” and “sounded like the sort of thing you do after a life in politics”.

Labor has seized on the revelation Mr Hockey had pushed for a tougher budget, with Treasury spokesman Chris Bowen arguing it was a “stark reminder of just how out of touch Australia's Treasurer is”.

“He doesn't know what it is like to sit around a kitchen table and to frame a family budget. That's the only conclusion the Australian people can reach if the Treasurer is boasting that he would have liked to go further.”

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