Details about what to expect on Tuesday night are still emerging, but here is what we know so far:

Speculation is mounting that the Treasurer will report a narrow surplus in this week's budget, something a federal government has failed to do for 15 years.

While Dr Chalmers hasn't confirmed the rumours, the government books are in a healthier position than expected thanks to tax revenue from surging commodity prices and more people in work.

The Albanese government has also promised $18 billion in new savings found from either ending programs or delaying others.

But taxpayers are expected to spend almost $18 billion dollars this financial year furnishing its debt - the second biggest expense after the National Disability Insurance Scheme.

Government debt reached almost $895 billion last October, and is projected to hit $1.1 trillion by mid-2026.

The Treasurer has promised the Budget will include a substantial cost-of-living relief package worth $14.6 billion over four years, consisting of power bill relief, energy efficiency investment, and welfare changes.

Speculation has been rife that the government will raise JobSeeker payments for Australians aged 55 and older, with Dr Chalmers noting on ABC radio that women in this demographic are "the most vulnerable part of the unemployed population".

The government has faced pressure - including from within its own ranks - to substantially increase JobSeeker payments, which currently amount to $49.50 a day for singles. Four Labor backbenchers recently signed onto a letter from the Australian Council for Social Service, calling to raise the rate.

While the Treasurer hasn't confirmed the partial JobSeeker increase, he told ABC radio that people over 60 years were already paid a higher rate "in recognition that it is harder to find a new job at that end of your working life".

Social Services Minister Amanda Rishworth elsewhere announced the government will invest $10.9 million through the second round of the Strong and Resilient Communities - Inclusive Communities Grants. The grants provide one-off funding for projects to support people aged 12-18, people with disability and mental health issues, vulnerable women, or unemployed people.

The government has set aside significant funding to crack down on tobacco and non-prescription vapes.

Health Minister Mark Butler said his government will lift the tax on tobacco products by 5 per cent each year for the next three years.

The change will come into effect from September 1, and will generate $3.3 billion in revenue for the next four years, including $290 million in GST payments to the states and territories, Mr Butler said.

The budget will also include $737 million to tackle harm caused by tobacco and vaping products. Within this, $264 million will be spent on a new national lung cancer screening program, which is expected to prevent more than 4080 deaths.

There will be $63 million put towards a public health information campaign to discourage people taking up smoking and vaping, and $30 million invested in support programs to help users quit.

A sum of $239 million will also go towards First Nations people affected by lung cancer, "with funding to ensure mainstream cancer services are culturally safe and accessible to First Nations people," Mr Butler said.

The funding commitments came not long after the government announced it will ban the importation and sale of non-prescription e-cigarettes, and place restrictions around colours, flavours and packaging.

Prime Minister Anthony Albanese announced there will be a $2.2 billion package to build a stronger Medicare system, including plans to expand the number of nurses, improve access to after-hours care, and introduce a patient ID system called MyMedicare.

The government will extend Medicare rebates for heart health assessments until June 30, 2025. These were originally due to expire next month.

It will also remove restrictions that are preventing First Nations people from claiming a heart health assessment within 12 months of an annual health check.

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The government announced it will abolish the controversial $484 million ParentsNext scheme from next year, and immediately drop mutual obligations requirements for current payment recipients until they are transitioned to a new support service.

Under the scheme - introduced by the Coalition in 2018 - parents of children aged between nine months and six years could have welfare payments suspended for non-compliance with requirements for meetings, study or parenting-related activities.

Nearly 100,000 people are on ParentsNext, the majority of whom are single mothers.

The Prime Minister has confirmed the government will also extend the single parent payment to those whose youngest child is below the age of 14.

The payment is currently only available to parents with children younger than eight. Parents with children older than eight currently need to apply for JobSeeker, meaning they receive less money and are classified as unemployed rather than as doing parenting work.

Single parents who would otherwise be taken off the payment, could now receive an extra $176.90 per fortnight, with the total package to cost the government $1.9 billion through to 2026-27 financial year.

Finance Minister Katy Gallagher told The Canberra Times that "this is the strongest budget for women in the past 40 years," and that a gender lens would be applied to every new proposal to find the impact on women.

Minister for Homelessness and Housing, Julie Collins, has promised a $67.5 million boost for homelessness services, topping up the National Housing and Homelessness Agreement for 2023-24.

The announcement came after the latest census revealed more than 120,000 people in Australia are homeless.

The government has announced it will also widen the National Housing Infrastructure Fund by a further $2 billion under this year's budget to help provide more social and affordable rental housing.

And in the ACT, the federal government and the ACT government will jointly fund a $11.64 million build-to-rent-to-buy pilot, which will offer at-risk Canberra women a chance to get on the path to home ownership. The plan will see 22 affordable long-term rental homes built in Belconnen, with construction due to begin in December.

More than 5 million households will receive up to $500 in power bill relief.

The relief will mostly be directed at aged pensioners and people on fixed incomes, including welfare recipients. The amount offered will also differ state-to-state, depending on how much electricity prices are and what amount state governments are prepared to contribute.

To help fund its cost-of-living package, the government is proposing changes to the petroleum resource rent tax that, if adopted, would raise another $2.4 billion over the next four years.

Energy Minister Chris Bowen has also shared that the government will establish a national energy transition authority, which will cost $23 million in its first year.

Called the National Net Zero Authority, the much-anticipated body will be tasked at supporting workers, industries and communities having an economic future as we transition to net zero.

Another $400 million will be set aside from the Powering the Regions Fund to support existing industry through an Industrial Transformation Stream.

Employers will be required to pay staff superannuation contributions at the same time they pay wages, in a change the Treasurer said will "make it easier for employees to keep track of their payments, and harder for them to be exploited by disreputable employers".

The changes will come into effect from July 1, 2026.

As part of the change, the government will also give the ATO extra resources to detect unpaid super and set greater targets for payment recovery.

Federal Early Education Minister Dr Anne Aly announced $72.4 million will be invested over five years in professional development opportunities for the early childhood education workforce.

The government will help fund a civics program to provide neutral, easy-to-understand information to voters about the constitution and referendum processes, ahead of the Voice to Parliament referendum this year.

To do so, it will provide $1 million to the Constitution Education Fund Australia and another $475,000 to the Museum of Australian Democracy.

The federal government will reallocate $19 billion in defence funding, following the scathing Defence Strategic Review released last month.

There is also speculation the Australian government and the United States are working together on a joint military assistance package for Ukraine, and which could be announced at the end of the month.

Dr Chalmers said that "we are a big supporter of the Ukrainian efforts to repel the Russian invaders and that will be represented in the budget".

The government has provided funding certainty for all the nation's nine main collecting institutions.

Prime Minister Anthony Albanese announced an extra $535 million over the next four years for the National National Gallery, Australian National Maritime Museum, Bundanon Trust, Museum of Australian Democracy (Old Parliament House), National Archives of Australia, National Film and Sound Archive, National Library of Australia, National Museum of Australia and the National Portrait Gallery of Australia.

The government handed a $33 million lifeline to the National Library of Australia's free digital platform, Trove, which was otherwise slated to close when its funding expired in June.

The budget will include $11.3 billion over four years to fund a 15 per cent pay rise for aged care workers, following orders from the Fair Work Commission to increase minimum wages in the sector.

The move will come into effect from July 1 and benefit 250,000 workers in the sector.