A state's debt burden will soar past $53 billion by 2030 but its treasurer insists budget surpluses and fiscal discipline will help steer it clear of a spiral into financial ruin.
Handing down the South Australian state budget on Thursday, Treasurer Tom Koutsantonis said it would provide certainty for business and relief for families.
"We are living within our means and this is a budget of no surprises and we're doing all of this without increasing taxes," he said.
"It's a responsible budget … that prioritises costs for families while delivering business stability."
But Opposition Leader Ashton Hurn said the interest bill would soon reach $10 million a day and wasn't manageable into the future.
"You don't need to be a brain surgeon to figure out that you can't pay off your credit card if you actually can't manage your own budgets," she said.
Mrs Hurn said Labor had blown its budgets by more than $6 billion in the past four years.
Net debt was $34.7 billion in 2025/26 and is forecast to reach $40.26 billion in 2026/27 and $53.6 billion by mid-2030.
Two major infrastructure projects were fuelling the debt, but the debt-to-revenue ratio was predicted to fall, which the treasurer said was a sign of a strong economy and manageable debt.
Much of the increased debt is attributable to the $15.4 billion Torrens to Darlington tunnel project, which will complete the city's north-south corridor link, and the Women's and Children's Hospital, with an estimated cost of $3.2 billion.
Mr Koutsantonis said he still expected the hospital to be built to the original budget and was "holding people's feet to the fire on this".
"We are not going to become Victoria. There is going to be budget discipline," he said.
A $223 million surplus is predicted for 2026/27, with surpluses across the four-year forward estimates totalling $1.4 billion.
The budget frames more than $500 million in spending as cost-of-living relief, including a $174 million commitment to deliver free public schooling from 2027, which the government says will save families more than $8000 per child across their education.
Mr Koutsantonis said it was the highest cost-of-living package in the state's history.
"We want South Australian businesses to know that we're on their side. We want families to know that we're there to help," he said.
Housing was the budget's big ticket item, with a $2.5 billion package that aims to deliver 2000 rent-to-own homes, secure land to fast-track development, facilitate new CBD apartment developments, and deliver 400 homes for first home buyers.
The $11 billion health budget includes an extra $1.7 billion to cover rising demand and increased costs.
The Thriving Kids program will receive $230.3 million to implement foundational supports, with the treasurer noting cuts to the NDIS were "one of the biggest threats" to state budgets.
The Australian Medical Association SA welcomed the increased health funding, but said the budget was missing smart funding and bold investments to treat the cause, "not just the ambulance queue".
A $50 million Research and Development Productivity Fund - which the premier said would attract "zero votes" - will support the growth of future industries.
The government would pass legislation to ensure the fund's long-term future because you don't invest in research and development today and get a return tomorrow, the premier said.
The government had already announced a partial freeze on recruiting of non-frontline public sector roles for the next 12 months, which is forecast to cut 1000 positions and save $120 million.
Shadow treasurer Ben Hood said the government set budget targets and had completely blown them.
"Twenty-seven out of 28 departments have blown their budgets, and some are quite eye-watering," he said.
The blowouts included the Department of Premier and Cabinet ($134 million) and SA Tourism ($85 million), he said.
An extra $90 million over five years will fund safety upgrades on the South Eastern Freeway as part of a joint state-federal project now costing $440 million.