Tony Abbott has acknowledged that voters may feel “dismayed” over broken election promises, but says he has kept all the core promises he made prior to coming into power.

“People may well feel dismayed, disappointed and occasionally even surprised,” Abbott said on the ABC’s 7:30 program on Thursday. “But I think that they also understand that governments have to respond to the circumstances they find themselves in.”

“We have kept faith with the Australian people because we have fundamentally honoured the core commitments which were to stop the boats, to repeal the carbon tax, to build the roads and to begin the tax of budget repair.”

But Abbott said he had been the victim of “unjustified cries of broken promises” from the opposition.

Abbott commended the work of his treasurer, Joe Hockey, who has been criticised for a series of gaffes and failing for to get key elements of the budget through parliament.

“Joe Hockey has been criticised lately but I tell you what, I think Joe’s going to be one of the great treasurers because he’s someone who bounces back,” Abbott said.

He also praised those seen as the best performers of his front bench: the immigration minister, Scott Morrison, the foreign minister, Julie Bishop, and the finance minister, Mathias Cormann, who he labelled “outstanding”.

Despite the praise, he hinted that a reshuffle might be on the cards.

“At some stage between now and the next election, quite probably,” he said.

On the question of whether he would stand aside, Abbott was more cautious, saying it was “a fair question”, but adding that “governments that change their leaders haven’t done very well lately”.

Abbott’s personal approval rating hit a five-month low in the latest Newspoll, prompting the prime minister to change tack, admitting the government’s performance had been “ragged” but assuring the public that the government had hit the “reset button”.

With just five sitting weeks until the next federal budget, Abbott has pledged to keep his pre-election promise on the economy.

“This government is deadly serious about getting back on the path to surplus,” he said.