Federal Opposition Leader Tony Abbott has used an early morning visit to a Melbourne fish market to bait the government about its carbon pricing scheme.
He accused Prime Minister Julia Gillard and Finance Minister Penny Wong of not knowing the finer details of their scheme.
"The finance minister couldn't explain the cost of the (carbon) tax," he told reporters.
The opposition leader was referring to an interview Senator Wong gave on Monday when she said the revenue from the sale of carbon permits was $18 billion, when government papers say it is $25 billion.
"And we now know the prime minister couldn't explain where the money was coming from ... to buy out Hazelwood (power station in Victoria)."
Ms Gillard on Tuesday said an undisclosed amount of money to buy back 2000 megawatts from the nation's highest-polluting coal-fired power stations would come from the budget's contingency fund.
"It's just not good enough," Mr Abbott said.
