Malcolm Turnbull has questioned Federal Treasurer Wayne Swan's experience and his ability to stick by his promises of 'tough decisions' in the upcoming budget.
"We are starting to see real impacts of this financial crisis, this international financial crisis and we've got to be very careful because there are jobs, homes, living standards at risk here if wrong decisions are taken," Mr Turnbull said.
"This is my concern with the treasurer. I really wonder whether he knows what he's doing.
"I mean, one minute he talks about the budget as though he's Robin Hood, robbing from the rich to give to the poor, the next minute he's making huge swinging cuts to spending to drive down inflation.
"What's it going to be?"
Coalition MPs are already branding the upcoming budget a ‘squib’, saying it's promising big, but will deliver very little.
It's Labor's first budget in 13 years and it's firming up to be the first real-test for the Rudd government.
The Prime Minister has already outlined big tax cuts for low income earners, and has made it clear, those on higher salaries will take a knock.
A means test for the Baby Bonus has become almost certain, while a tax hike on prestige cars and changes to the medicare levy have been locked in.
However, Shadow Minister Tony Abbott thinks it's all window dressing.
"I think the budget will be a squib, I think there will be cosmetic spending cuts, cosmetic tax increases," he said.
The attention is also on the Opposition Leader Brendan Nelson, who's facing a leadership coup if his performance doesn't improve.