Prime Minister Tony Abbott has seized on a report suggesting Australia's borrowing costs could go up if the government's budget is not passed.
Ratings agency Standard & Poor's has warned Australia's AAA credit rating could be reviewed unless significant cuts are made to the budget.
Mr Abbott said the Labor opposition for putting the nation's rating at risk.
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"Labor were vandals in government and it looks like they want to continue to be vandals in opposition," Mr Abbott said.
The agency's leading sovereign analyst Craig Michaels has warned Australia's rating might need to be reviewed if the coalition is unable to pass at least "some" of the $37 billion in savings announced in last week's budget.
Labor has vowed to block about $18 billion in cuts and tax hikes. Crossbench parties have also threatened to veto some of the measures.
Mr Abbott said Australia would be forced to pay higher interest on its debt if it loses its triple A rating.
That would mean even more than the billion dollars a month being paid on current borrowings.
He said the government has a plan to tackle Labor's debt and deficit "disaster".
"Until such time Labor comes up with a plan of its own they are nothing but fiscal vandals," he told reporters in Canberra on Tuesday.
Opposition Leader Bill Shorten said it was Labor that achieved a triple-A rating from world's three major rating agencies for the first time. Australia was one of only eight countries to do so.
"If Tony Abbott squanders our triple-A rating, then it is on his head," Mr Shorten told reporters in Brisbane.
"It's on their watch, their issue."
