Liberal MP slams his government's budget

A disgruntled Liberal MP has slammed his government's budget, describing it as a fudged opportunity.

Dennis Jensen, who has lost preselection for his West Australian seat, took to social media on Wednesday morning to criticise the lack of any action to rein in "rampant spending".

"We simply cannot go on like this. This is just like Wayne Swan and `the four years of surpluses I announce tonight'. Where is someone like a Peter Costello when you need him?" the MP posted on his Facebook page.

Dr Jensen described the small business tax cuts as a "good thing".

"But seriously, going 10 years into the future?" he said of the extended plan to lower the company tax rate from 30 per cent to 25 per cent.

The MP contrasted the government's first term with that of the Howard government, where real things were done to bring down debt.

"Here it is being added to ... shame."

Dr Jensen later said the budget essentially did nothing, especially to address growing debt.

He labelled as "heroic" the assumptions by Treasury, especially a growth rate increasing by more than one per cent.

"Which, quite frankly, the treasurer should know are unrealistic," he told reporters at Parliament House.

"He may well quote the Treasury, but the problem is the Treasury has been wrong and heroic in terms of assumptions that they've made in the last eight years or so."