Treasurer Jim Chalmers says the federal government is confident the $14 billion cost-of-living package will not add pressure to inflation due to its "responsible" spending.
The heavily promoted budget package will include energy price relief, expected to flow to 5.5 million households and one million businesses.
Investments in cheaper medicines and tax incentives for electrification and energy efficiency upgrades will also fall under the total $14.6b over four years, targeting acute cost-of-living pressures.
Speaking ahead of the budget, to be unveiled on Tuesday night, Dr Chalmers said the government had taken a "much more responsible approach" to the higher tax revenue and record commodity prices.
"We're confident what we've done here is provided some cost-of-living relief for people doing it tough, but conscious that we've got this inflationary challenge in our economy," he told ABC Radio on Monday.
"We need to be responsible about what we spend, and that's what we've done.
"My predecessors used to spend most of those upward revisions to revenue. I have saved most of it."
Dr Chalmers denied he had gone too soft on the oil and gas sector after announcing changes to the petroleum resources rent tax which will raise $2.4 billion if legislated, after the industry's peak body accepted the changes.
"Some people will say we should tax more, some people will say we should tax less, I think we've struck the right balance here," he said.
Opposition finance spokeswoman Jane Hume said the only way to provide genuine relief for struggling families was for the government to rein in its spending and tackle inflation.
"Getting inflation down is the only policy that would provide the cost-of-living relief to all Australians," she said.
Senator Hume said the government had palmed off its responsibility to help bring down inflation to the Reserve Bank.
More government plans to support households and businesses through the period of sky-high inflation will be revealed.
Jobseekers will be looking for a boost to income support payments following reports the government has locked in a $40-a-fortnight boost.
The latest reports follow speculation last week that any uplift would be limited to over-55s.
The Greens have already taken aim at the possibility of a $40-a-fortnight increase that would equate to a "paltry" extra $2.85 a day.
The government has also managed to find $17.8b in budget savings and shifted spending, with the finance minister accusing the former coalition government of "tricky budgeting tactics and dishonesty".
The savings include $7.8b in re-prioritisations already outlined as part of the Defence Strategic Review.
Finance Minister Katy Gallagher said the cost-of-living relief was a "significant package" in scale and reach.
"This is a very strong budget in terms of support for vulnerable Australians ... to investing in the future and also putting the budget on a more sustainable footing going forward," she told ABC News on Monday.
Asked about the re-prioritisation of money, Senator Gallagher said the government's approach had not been to "slash, cut and burn" but to target funding to address future needs and pressures.
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