Every Australian deserves cost-of-living relief, including the nation’s highest earners, the prime minister says.

Anthony Albanese on Wednesday took to the press gallery to defend his government’s third budget, which includes a $300 energy rebate for all households, as well as a price cap on medicines, a boost to rent assistance and cuts for all taxpayers that will kick in from July.

The government has come under scrutiny for its energy bill relief, with critics claiming it will go to those who do not need help, but Mr Albanese maintains it must not be means tested.

“We want to make sure that every Australian gets support during what is a cost of living crisis, which everyone is feeling,” he told the Today Show.

Asked if billionaire mining magnate Gina Rinehart also needed help with her power bills, he stood by the budget proposal.

“This is the most effective way to deliver support across the board,” he said.

“Gina – if she pays income tax – will get a tax cut, as well as every Australian.

“That is because, right throughout the income scales, there are pressures on that as well.”

More than 10 million households will receive the $300 energy bill rebate, to be paid as a $75 credit on each quarterly bill, while small businesses will receive $325.

Commonwealth rent assistance has also been bolstered by 10 per cent, with those on the payments to receive an extra $19 on average per fortnight.

The cost of medicines will be frozen, with prescriptions for medicines on the Pharmaceutical Benefits Scheme to be capped at $31.60, as well as limits of $7.70 for concessions and pensioners.

Opposition Leader Peter Dutton says the coalition will support measures that provide relief but he was still worried about the budget’s impact on inflation.

“The best thing that the government could have done in this budget was to be responsible to take the pressure off homegrown inflation and to try reduce interest rates,” he told ABC radio.

“This is a smoke and mirrors game going on here and giving $300 to people … is just not going to cut it for the average family.”

The Australian Council of Social Service said the budget had a “gaping hole” in its heart by not having an increase in unemployment payments and income support.

“It cruelly denies the increase in income support that over one million people struggling to survive on JobSeeker and Youth Allowance desperately need,” the organisation said in a statement.

“Extending (the energy rebate) to everyone – regardless of income – is extraordinarily wasteful.”

Treasurer Jim Chalmers emphasised that the primary motivation behind the budget was to help those doing it tough.

Asked why more assistance wasn’t offered to those on income support, he maintained middle Australia was also feeling hip pocket pain and noted that means testing energy help would be less efficient.

“This relief is delivered via the (energy) retailers – they don’t have information about people’s incomes and so you would have to take a long time, and spend a lot of money and effort to design a system … that doesn’t exist right now,” he told the ABC.

Greens leader Adam Bandt said the budget was a betrayal of renters, women, students and mortgage holders.

He said the government is posting an expected $9.3 billion surplus for 2023/24 at the expense of many of those hit by high prices.

“In a cost-of-living crisis, a surplus isn’t an achievement. Labor’s surplus won’t put food on the table or pay bills for a struggling family,” he said.

The treasurer will further spruik the federal budget when he addresses the National Press Club on Wednesday.

By Andrew Brown and Kat Wong in Canberra