Tony Abbott does not expect a rapturous response when his government implements the recommendations of its commission of audit.
But the prime minister rebuffed suggestions the review would recommend tax increases, even though Australians understood they had to carry some of the load for the country's fiscal recovery.
"If we are going to get debt under control, if we're going to get the budget back in the black, yes, inevitably things will have to change," Mr Abbott told Fairfax Radio on Wednesday.
He warned there would be some things people would not like.
"But I think the public understand that government has been living beyond its means."
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A day after Treasurer Joe Hockey announced the audit, to be headed by Business Council of Australia president Tony Shepherd, the government is already facing questions about spending cuts.
The root-and-branch audit - the first since 1996 - will look for ways the government can save money, remove duplication and raise extra revenue to balance the books.
Mr Abbott said the commission had a mandate to go through government "branch by branch, division by division, agency by agency".
However, it was "almost inconceivable" the commission would go down the path of recommending tax increases.
Mr Abbott did foreshadow cuts to the public service - promised before the September election - saying there were 20,000 more workers employed by the commonwealth than at the end of the Howard government in 2007.
As well there may be "some services that can be better delivered".
"The important thing is to get the best possible services for the lowest possible cost to taxpayers, and that is what we are exploring right now."
The opposition has accused Mr Hockey of abandoning a pre-election pledge not to cut from the health, education and defence budgets.
The treasurer says any savings identified by the commission will be reallocated within those three key portfolios.
Labor's finance spokesman Tony Burke questioned how savings in areas such as health could not be considered "cuts".
"You can slash money to hospitals, but if you're putting a new drug on the PBS at the same time, that won't constitute a cut," he told ABC radio.
