'More than one way to help the vulnerable' in budget: Chalmers

"There's more than one way to help people who are doing it toughest and who are the most vulnerable people in our society," Dr Chalmers told ACM, publisher of this masthead.

"We have shown a willingness over the past two years, and there's a willingness in the budget, to recognise the pressure that people are under, particularly the most vulnerable Australians. There is more than one way to help them and you'll see that in the budget."

The budget is expected to lift the Commonwealth rent assistance payment further after hiking it last year but not to give JobSeeker, which increased by $40 per week last year, the same treatment. The Economic Inclusion Advisory Committee said it remained woefully inadequate.

"We've shown our bona fides when it comes to investing in housing and people should expect more of that on Tuesday," Dr Chalmers said in an interview.

Asked by how much rent assistance could be lifted, he said: "We know that a big part of this inflation challenge is rent. And so, housing policy won't be ignored in the budget - far from it. It will be a central feature."

He said the average tax cut in the budget worked out to be "about $36 a week to help with the cost-of-living pressure ... right up and down the income scale".

"There'll be additional cost-of-living help on top of that, and that will flow in the next 12 months," he said.

The Treasurer, who has ruled out abolishing negative gearing in the budget, said he still hoped to deliver a second consecutive surplus on Tuesday.

"That would be the first back-to-back surplus in almost two decades - and we would see that as an important way to put downward pressure on inflation," he said. "We'll run the final numbers in the next day or two and we'll get a firmer view of that ... it makes sure that we can make room for our priorities, including housing and universities reform and cost of living relief."

Dr Chalmers said he would make clear in the budget whether inflation, now at 3.6 per cent, would hit 3.8 per cent as forecast by the Reserve Bank last week, once the budget changes were factored in. The Treasurer said he would have more to say about tax in the budget.

"I believe in tax reform which is methodical and considered and sequenced. My approach [is] to do things in a way which brings people along with us," he said.