Debt repayments have been flagged as one of five key areas of spending ahead of the October 25 budget, alongside aged care, disability care, hospitals and defence.
Treasurer Jim Chalmers on Friday will reveal how much spending in the areas is expected to grow when he speaks at an investment event hosted by the Queensland government.
The cost of servicing government debt is expected to grow by 14 per cent each year, outpacing increases in the other big-spending areas.
Mr Chalmers says spending on the NDIS will grow by 12.1 per cent each year, health by 6.1 per cent and aged care by five per cent.
Defence spending will grow by 4.4 per cent per year, on average, over the next four years.
The government has also downgraded its forecasts for global growth and warns the Australian economy and budget will not be spared from the turbulence.
The treasurer expects global growth to be 0.75 per cent less than anticipated by 2022 and one per cent lower in 2023 than previously forecast.
"The risk of major economic downturns is rising, not receding," Dr Chalmers will say on Friday.
"And the impact this has on Australia's economy and budget is hardening, not softening."
The downbeat predictions came as debate rages over tax cuts due to come in mid-2024, with the government refusing to rule out making changes to the legislated measures.
Education Minister Jason Clare says the government is preparing to make tough decisions in the budgets with the international economy worsening and fiscal pressures growing.
"We have to make sure that we don't do anything that is going to make a reserve bank's job harder," he told Seven's Sunrise program.
"Where we do invest more, like more investment in childcare, it's designed to boost productivity rather than make the situation worse."
Opposition Leader Peter Dutton said the failure of ministers to give a straight answer about the future of the cuts echoed previous broken promises from Labor governments.
"The prime minister looked the Australian public in the eye and gave them a solemn promise," he told the Nine Network.
"That is, people on incomes of $45,000 to $200,000 would pay no more than 30 cents in the dollar. That's a big win for families who are struggling to pay their power prices, their gas bills, their fuel."
Mr Dutton said families had entered into home loans on the basis that no major party would touch the legislated cuts and any change would constitute "a complete betrayal of that trust".
Dr Chalmers will also note aggressive rate hikes from central banks worldwide - particularly the US Federal Reserve - have put pressure on the value of the Australian dollar.
"Weakness in the currency means that some of the things we buy from overseas become more expensive, making the already hard job of the Reserve Bank of Australia harder," he says.
On Tuesday, the RBA became the first major central bank to shift to a slower pace of tightening, with a 25 basis point rise confounding expectations of a 50-point rise.
The updated predictions will be released in full in the October 25 budget.
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