The Coalition has not submitted its climate change, broadband and asylum seeker policies for independent costing ahead of Thursday's final release of figures before the election.
Shadow treasurer Joe Hockey will reveal the Coalition's election costings on Thursday, leaving voters just hours to digest the numbers while also refusing to say when the budget would return to surplus. The precise time that he will release the costings has not been announced.
After five weeks of campaigning and a sustained political argument over the final budget impact of the Coalition's spending and savings plans, Mr Hockey will reveal his list of policy costings on the penultimate day of the campaign, promising only that the budget would be ''in excess of $6 billion'' better off in cash terms under his stewardship, and that gross debt would be $16 billion lower.
But missing from the independent costings will be the analysis on three of the Coalition's key policies: broadband, Direct Action and the plan to stop asylum seekers coming to Australia by boat.
The reason that the Coalition has not sent these policies to the independent Parliamentary Budget Office was because the PBO will not have access to the information outside of government and because the policies have "input from a range of external sources", a spokesman for Mr Hockey confirmed.
Instead of being costed by the PBO, those three policies would be verified by the Coalition's so-called ''eminent persons'' panel comprising former top bureaucrat Peter Shergold, economist Geoff Carmody and former Queensland auditor-general Len Scanlan.
The three men have been locked in the Liberal Party's Melbourne campaign headquarters in recent days scouring the numbers to ensure that the errors of the last election, when Treasury found an $11 billion hole in Coalition figures, are not repeated.
On Thursday, while campaigning in Brisbane, Mr Abbott defended the Coalition's approach to costings.
''No opposition in our history has been as thorough and as prudent . . . in respect of its costings and its policies than this Opposition,'' he said.
The Coalition Leader also defended the last-minute release of the opposition's costings: ''this is not the first word, this is the final word.''
He said that ''all the way through'' the Coalition had been giving voters the costs of its policies and talking about the ''responsible savings'' it would make.
''We want the Australian public to know that we have absolutely nothing to hide,'' Mr Abbott continued.
On the policies not submitted for costings, Mr Abbott said that the NBN policy was announced ''many months ago'' and was a ''much better deal'' than the Labor policy.
''The government's been crawling all over it, no one has been able to question the costings. It is absolutely bullet proof.''
He said the Direct Action plan had been to the Treasury in 2010 and the department had found ''no fault with it''.
''Another bullet-proof policy,'' Mr Abbott said.
The Coalition Leader left the door open to harsher cuts, should he be elected on September 7, noting that his promised Commission of Audit would ''go through the whole of the administration''.
''I'm very happy to have the Commission of Audit go through the whole of the administration, to tell us whether, in their opinion, they think things can be done better. And where things can be done better, more frugally, more prudently, with more benefit for taxpayers, surely it would be a foolish government that would ignore that,'' he said.
Mr Abbott has long pledged that if he wins Saturday's election he will set up a commission of audit similar to that commissioned by former prime minister John Howard when he took power in 1996. Labor has accused the Coalition of using the audit to hide spending cuts and policies until after the election.
Mr Hockey will argue on Thursday that the economy will grow faster under the Coalition, and that billions of dollars of red-tape costs could be stripped away.
The shadow treasurer's office also confirmed that a Coalition government would, as part of its proposed Commission of Audit, redirect millions of dollars of "obscure research grants" into projects deemed more worthy, such as finding cures for dementia and other diseases.
The election campaign is now into the final stretch with a ban on election advertising in effect from midnight Wednesday.
With the Coalition well in front in the polls, Opposition Leader Tony Abbott has admitted the election is make or break for him, telling the ABC's Kitchen Cabinet cooking show: ''I think one thing we can be absolutely certain of is that I won't be the Opposition Leader after the election.''
Labor has laid out $54.6 billion in combined deficits over the coming three years but promises to have the federal books showing a small $4.2 billion surplus in 2016-17.
Mr Hockey's refusal to outline a path to surplus is expected to bring an attack from Prime Minister Kevin Rudd, who will make his final campaign set-piece speech at the National Press Club in Canberra on Thursday.
Mr Rudd will seek to capitalise on Labor's success in steering Australia through the global financial crisis in 2008-09.
A Labor source said Mr Rudd would ''strongly defend this record against a Liberal vision of the GFC, which would have been to cut deep and look after the interests of a few''.
Mr Rudd is also expected to claim that the Coalition has big cuts planned that voters will only learn about once an audit of spending is completed.