The federal opposition has labelled as "just plain dumb stuff" the prospect of a taxpayer levy for the flood rebuilding task.
Prime Minister Julia Gillard later on Thursday will outline the government's plan to pay for repairing roads, bridges and rail lines mainly in flood-ravaged Queensland.
The government is facing a repair bill of more than $5 billion before taking into account the revenue losses caused by the broader impact of the floods on the economy.
The plan will include a fixed-term levy to the Medicare impost that will cost the average taxpayer about $6 a week.
The opposition argues a levy on taxpayers is unnecessary, saying cuts to government spending is a better option.
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Opposition treasury spokesman Joe Hockey says the levy will come on top of tax increases on tobacco, alcohol and cars, and planned imposts on minerals and electricity.
"All of those things on top of actual increases in prices of food and staple products for the family and then the government imposes a levy on top," he told ABC Radio.
"It's just plain stupid, dumb stuff."
Mr Hockey said the levy would cost more than the estimated $300 an average wage earner would pay under a minimum 0.5 per cent increase to the Medicare charge.
"It will be much more for many others," he said, adding people earning between $60,000 and $100,000 would be "particularly hit".
The coalition's opposition to a flood levy has won backing from Reserve Bank board member Warwick McKibbin, who warned the tax increase could deliver another kick to an economy already hit by the floods.
Professor McKibbin said the new tax on households would slow consumer spending unnecessarily.
He called on the government to accept a temporary increase in the budget deficit to cover the rebuilding.
"The worst thing you can do is to stick to a fiscal deficit target for no reason except that it's a political target, and contract parts of the economy to raise revenue when you've had a shock that's hurt the economy," he told The Australian on Thursday.
Finance Minister Penny Wong, ahead of a cabinet meeting on Thursday morning, dismissed any need to change the government's target of returning the budget to surplus in 2012/13.
"We're focused on doing the right thing for the nation," she told ABC Radio.
That meant "thinking first" about things to do now to rebuild Queensland and other flood-affected areas.
The government also had to recognise where the economy was going, Senator Wong said.
"We do have very strong economic fundamentals, we do have a very strong pipeline of investment and you'd anticipate in a couple of years' time that we would see the economy running close to capacity."
Senator Wong said the floods required an extraordinary response from the government.
"We've been very clear with the Australian people, we have to find the resources to do this," she said.
"There will be significant cuts - there are hard decisions, but we have made them to find the resources needed to rebuild Queensland."
