Ms Gillard, in the French resort city of Cannes for the G20 leaders summit, says Australia is prepared to boost its contribution to the International Monetary Fund (IMF) to safeguard the global economy.
Opposition treasury spokesman Joe Hockey says the coalition has no problem giving more funds to the IMF, but described the prime minister's announcement as "astonishing".
"The suggestion that we should be putting money into the IMF to bail out the Eurozone when not even the British are prepared to do so is extraordinary," he told reporters in Canberra on Thursday.
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"The prime minister needs to explain to the Australian people immediately how much money she wants to put into a bailout."
TAXPAYERS FIRST: HOCKEY
Mr Hockey later told ABC Radio that the coalition had "grave concerns" Australian taxpayers would be seen to be bailing out the largest economy in the world.
"We do have a problem giving the Europeans a get-out-of-jail-free card by offering them additional funds through the IMF when they need to resolve this issue themselves and fast."
Ms Gillard was ignoring the fact that Australia was running a deficit and the government would have to increase borrowings to give more funds to the IMF, he said.
The most recent Treasury forecast has the budget heading to a $22.6 billion deficit in 2011/12 and a return to surplus in 2012/13.
"Therefore we will be borrowing money to lend to the Europeans who in turn will be lending to Greece," Mr Hockey said.
