The prime minister has distanced himself from controversial remarks by the treasurer, Joe Hockey, that poor people “don’t have cars or actually don’t drive very far”.

As criticism grows within the Coalition about the treasurer’s clumsy attempts to explain the budget, Tony Abbott was asked whether he endorsed the comments made by Hockey in an attempt to explain the reintroduction of indexation for fuel excise.

“Plainly I wouldn’t say that, but I do want to make it clear the best thing we can do for all Australians, rich and poor alike, is to get the budget back under control,” he replied.

“... whatever people may think about the way Joe has expressed himself in a particular radio interview, he has a plan to make sure all Australians are better off in the longer term.”

Asked whether the treasurer continued to enjoy his full support, Abbott said “of course” but then again quickly switched to a defence of the budget itself, the economic case for reducing government expenditure and the difficulties of saying to people: “the benefits you were told you can have are not affordable, they were never affordable”.

Asked again whether he believed government ministers, including the treasurer, were “out of touch” with the lives of ordinary Australians, the prime minister again deflected the question, this time to a discussion of the now-repealed carbon tax.

“You know one of the reasons we were so determined to get rid of the carbon tax is that we know a lot of Australians are doing it tough and the carbon tax was a gratuitous assault on their hip pocket.” He added: “I am very proud of the budget the treasurer and I have brought down.”

Earlier in the week Hockey used Australian Bureau of Statistics figures showing the absolute amounts spent by different income groups on petrol to defend his comment about poor people and cars. But he was quickly challenged on the basis of the same figures.

Analysis of the figures showed that, expressed as a percentage of mean income for the same groups, petrol spending represented 4.54% of income for the lowest-earning households but only 1.37% for the highest-earning ones.

Speaking on the Nine Network on Friday, the education minister, Chris Pyne, refused to say whether he agreed with Hockey’s remarks, but did say he believed the treasurer was “doing an inspirational job”.

Some Coalition MPs, including Liberal senators Cory Bernardi and Ian Macdonald, have gone on the record to criticise the comments. Many others have expressed private dismay.

The re-indexation of fuel excise appears unlikely to pass the Senate.