He said presenting the budget as a complete package for dealing with Australia's economic and financial problems had made it look as if the government was concentrating on spending cuts and not enough on taxation, leading to claims it was "unfair".

"If you start from a presumption that you have a problem on the outlays side, and you have a very highly targeted welfare system and you think you need to take action on outlays, inevitably the people who get most from that system are going to complain," he said.

While fairness was important, it was ridiculous to suggest that every element in the budget needed to be fair, he said.

"Whenever you do, there are going to be losers. If the discussion is always about whether anyone loses then society as a whole can never be better off.

"A classic example is the debate over indexation of the fuel excise. What is important is how much it would add to the cost of a litre of petrol over the course of a year. That got lost. The materiality of what we were talking about got lost in a debate about whether or not it was seen as fair. We have to find ways to have more mature discussion than that."