Treasurer Joe Hockey has been labelled "out of touch" after claiming that the poorest won't be hit by increases in petrol tax because they don't own cars.

The treasurer is standing by his statement, even releasing figures he says prove he's right.

The row has angered many, as negotiations over the Budget reach a critical point.

Mr Hockey has been racking up some serious air miles, visiting cross-bench senators to sell his Budget.

Labor says his feet aren't on the ground, attacking the Treasurer for claiming an increased petrol tax will hit the wealthy hardest.

"The poorest people either don't have cars, or actually don't drive very far in many cases," Mr Hockey said.

He was quickly taken to task by the opposition.

"Are you serious Joe Hockey? Are you really the caricature - the cigar chomping leghorn foghorn of Australian politics - where you're saying poor people don't drive cars?" said opposition leader Bill Shorten.

Three months after the budget was handed down, billions in savings and revenue are still in limbo. Despite Mr Hockey's negotiations the Government's so far failed to win over enough support to pass key reforms, although there are signs the Treasurer is willing to give a little.

There's some sympathy for the Treasurer.

"I'm a bit concerned about Joe because it seems he's had the rest of his party do a runner on him," said the Palmer United Party's Jacqui Lambie.



According to Senator Lambie, that includes the Prime Minister, who's been in London for briefings on Iraq.