The government has reached an in-principle commercial settlement with the operators of the hospital over a range of problems, including dodgy duress alarms and construction faults.

It is expected to cost the government about $16 million on top of the $18 million already spent on legal fees.

"This has been an absolute lawyers' picnic costing all parties tens of millions of dollars,'' Mr Lucas said.

The new Royal Adelaide Hospital opened in September 2017 at a cost of $2.4 billion, about $600 million over its original budget.

However, a range of problems quickly emerged including issues with the duress alarm system and the airconditioning system.

Under the terms of the settlement, the hospital's operators Celsus will design and construct two new cooling towers as well as complete a range of other work.

Mr Lucas said the settlement had been backed by treasury, SA Health, the crown solicitor and a team of private legal advisers as in the state's best interest.

Health Minister Stephen Wade said it was a key milestone in the organisational and financial turnaround at the Royal Adelaide.

"This agreement allows our hard-working staff to focus on providing the very best health care for South Australians and builds on the momentum of change occurring in our central hospitals," he said.

Australian Associated Press