Even if Australian Prime Minister Tony Abbott is out of the country, former PM John Howard did not spare him from a rebuke for Mr Abbott's alleged heavy reliance on slogans and the belief that Aussies would support changes if they perceive these to be fundamentally fair.

Mt Howard, the PM from 1996 to 2007, was quoted by The Sydney Morning Herald as saying, "We sometimes lose the capacity to argue the case - we think that it sufficient that we utter slogans."

The ex-PM actually did not name Mr Abbott, but the Opposition piggy backed on the comment, with Labor leader Bill Shorten saying, "John Howard must be beside himself watching Tony Abbott botch his first budget like this."

Another former PM, Bob Hawke, said he is alarmed by the quality of the debate at the federal Parliament. Mr Hawke led Australia from 1983 to 1991.

Mr Howard acknowledged that the Abbott government is in an unenviable position and could lost if an election were held, but he believes the surveys would eventually change.

But he also warned the Opposition that "You can't expect, nor should you expect of the Australian public, their support to throw out an existing government and put you in unless you have done them the courtesy, and the country the service, of working out a coherent policy."

The two former PMs shared on Wednesday their thoughts about Australian politics to mark 50 years of political debate at Canberra's National Press Club.

Mr Howard said that while slogans and arguments are important in politics, "we have sometimes lost the capacity to respect the ability of the Australian people to absorb a detailed argument."

He explained that Aussies would respond to an argument for change and reform, but they must be satisfied that it would be in the national interest and it is fundamentally fair because of their deep sense of nationalism and patriotism.

Mr Hawke added, "I think Parliament is held, if not in contempt, in disdain and I do think that something ought to be done to lift the quality of performance in the Parliament."