Nervous shoppers are threatening to close their wallets following the Coalition's hard-hitting budget, with consumer confidence falling at the fastest rate since before the global financial crisis, a major bank survey shows.

The ANZ-Roy Morgan Consumer Confidence survey charted a fall of 3.2 per cent since the budget, taking its index to 100.4 - a significant 14 points lower in a month and the fastest rate of descent since October 2008.

The dire news is fuelling retailers' fears that the budget itself, including the messy politics engulfing it, may have dampened business investment and consumer sentiment just when economic growth was showing signs of improved health.

With the country gripped by a political stand-off over several contentious measures, Prime Minister Tony Abbott again insisted that no promises had been broken while Treasurer Joe Hockey warned the economy would ''fall apart'' if Labor refused to pass key budget measures in the Senate.

''I don't accept that there's been any breach of faith,'' Mr Abbott told reporters in Canberra.

He leapt on a report in the financial press suggesting the country's top-line credit rating could be at risk if budget savings were blocked by the Greens and Labor.

''If these necessary measures don't pass the Senate, our triple-A credit rating is at risk and if we lose our triple-A credit rating we pay higher rates of interest on our debt and that means it's even more than a billion dollars a month, every single month, just to pay the interest on the borrowings,'' he said.

However, Standard and Poors analyst Craig Michaels clarified his agency's position on Tuesday, telling the ABC's World Today program that the perception that Australia's triple-A rating was contingent on specific budget measures was not correct.

But consumers remain to be convinced the Coalition's formula of winding back welfare, cutting public servants and imposing new taxes such as the GP charge is the right answer.

The bank's head of Australian economics Justin Fabo said the findings suggested the fact that people were worried might be enough to slow things down.

"While the budget revealed some changes to welfare eligibility and taxes which may weigh a little on consumer spending directly over the next few years, the indirect impacts of these announcements on consumer confidence could prove to be more important,'' he said. ''The persistence of this fall will, however, be important to the assessment of the consumer spending outlook."

That view was backed by Bank of America Merrill Lynch chief economist Saul Eslake who said it was the perception of the budget that may be more damaging than the severity of any actions themselves.

''This is the thing about sentiment. People may think something is not good, but does it actually affect them personally - maybe not, and that's why it is only sustained movements in either direction in consumer confidence that really do tell you anything about what might actually be happening to how people spend,'' he said. ''It's not a good sign, but whether it's a material sign is another question that you'd need a few more data points before you draw a conclusion.''

The government began a major rhetorical offensive on Tuesday, hoping to regain control of the difficult public relations task of selling its budget, which has already sent its popularity plummeting in two key opinion polls.

In a move designed to shift the blame to Labor, Mr Hockey said it was ''emphatically opposing'' $40 billion in savings, including $5 billion in savings that the opposition itself had proposed before the last election.

''It is one thing for Labor to be the complaints desk of the nation but they also have a responsibility because they have the numbers in the Senate to block the initiatives of the government,'' Mr Hockey said. ''Bill Shorten's now preventing us from keeping our promises.''

Shadow treasurer Chris Bowen said Mr Hockey's complaints were laughable when, in opposition, he had opposed "tens of billions worth of structural savings".

Mr Bowen said Labor would work constructively with the government to implement budget measures that were fair and reasonable, but the party would not rubber-stamp broken promises on Medicare, pensions and higher education fees.

With Lisa Cox

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