Prime Minister Tony Abbott is willing to make adjustments to his unpopular budget, but won’t be making fundamental changes.

Tony Abbott has bitten the bullet after several weeks of ministerial floundering, indicating he’ll consider alternatives to tough budget measures.

But any adjustments will only go so far.

“What we’re not prepared to do is sell out the fundamentals,” the prime minister said on Monday.

The coalition has indicated it will consider alterations to its planned $7 GP co-payment, tougher welfare rules and deregulation of university fees – all of which face opposition in the Senate.

“If you don’t like what the government is putting up, give us your alternative,” Mr Abbott said.

“There was some alternatives that came up from one of the crossbench members of the federal parliament and, frankly, they didn’t stack up for five minutes.”

Labor and the Australian Greens have told the government to go back to the drawing board three months after the budget was handed down by Treasurer Joe Hockey.

Shadow treasurer Chris Bowen says Mr Hockey has lost control of the budget narrative.

“No amount of tinkering, no amount of window dressing, no amount of cosmetics will change the fundamental unfairness of this budget,” he told reporters in Canberra.

Former Labor treasurer Wayne Swan also offered the prime minister some free advice, saying the problem with the budget is not its salesmen, but its substance.

He dismissed as “phoney” government claims about a budget emergency and crisis.

Mr Swan used an address to the National Press Club, following the launch of his new book – The Good Fight: Six Years, Two Prime Ministers and Staring Down the Great Recession – to provide an insight into how the Labor government of the time responded to the global financial crisis.

“It is important to show what a real emergency was and … how we dealt with (it),” he said.

Independent senator Nick Xenophon said talk of adjustments reminded him of going to the chiropractor rather than the “radical surgery” that was needed.

Palmer United Party leader Clive Palmer again labelled the budget unfair, saying it was not something his senators could support.