Treasurer Joe Hockey has warned that household budgets will suffer if Australia loses its triple-A credit rating.

It’s not the sort of thing people will want to hear, given that many are already reeling from last week’s federal budget, which sent confidence tumbling at its fastest pace since the depths of the global financial crisis.

The government has seized on a report that credit rating agency Standard & Poor’s may need to review Australia’s rating if “some” budget savings don’t clear parliament.

However, a Standard and Poor’s spokesman told Guardian Australia that is unlikely, with less than a 33 per cent chance the rating could be downgraded, even if the measures aren’t approved.

“It would have an impact on every household that borrows money, either through a mortgage or credit card,” Mr Hockey told reporters in Sydney on Tuesday.

Labor has vowed to use its Senate numbers to help block about half of the government’s $37 billion in savings, leading Prime Minister Tony Abbott to take aim at the opposition.

“Labor were vandals in government and it looks like they want to continue to be vandals in opposition,” he told reporters in Canberra.

Opposition Leader Bill Shorten reminded the prime minister that it was Labor that achieved a triple-A rating from the world’s three major rating agencies for the first time.

“If Tony Abbott squanders our triple-A rating, then it is on his head,” he told reporters in Brisbane.

Mr Hockey calculates that with interest charges Labor is opposing some $40 billion of savings.

It also includes $20 billion of measures that both the coalition and Labor took to the 2013 election but are stuck in the Senate.

It was one thing for Labor to be the “complaints desk of the nation”, but Mr Shorten also had to identify his savings, the treasurer said.

“Otherwise things will start to fall apart.”

Shadow treasurer Chris Bowen dismissed Mr Hockey’s comments as “laughable”, citing the coalition’s opposition to structural savings amounting to tens of billions of dollars while Labor was in government.

“Labor will not be a rubber stamp for Tony Abbott’s broken promises,” he told AAP.

The ANZ-Roy Morgan consumer confidence index has fallen a further 3.2 per cent in the past week and a hefty 14 per cent in four weeks when budget leaks first began to emerge.

It was the steepest four-week decline since October 2008.

Treasury Secretary Martin Parkinson concedes the government has taken hard policy choices.

“It is also useful to recall that the economic reforms during the 1980s and 1990s faced stiff opposition at the time,” he told the Australian Business Economists lunch in Sydney.

However, they transformed Australia into a globally competitive economy and set it up for more than two decades of continuous economic growth.

AAP