SA premier defends 'first-class' hospital

South Australia's premier has accused the opposition of making "gross exaggerations" about ongoing problems with the new Royal Adelaide Hospital.

Jay Weatherill says taxpayers have been largely insulated from unexpected costs associated with the $2.1 billion project, which is months behind schedule and at least $400 million over budget.

"This is going to be a first-class hospital which will meet the needs of our citizens," he told a budget estimates hearing on Thursday.

"In the fullness of time it will present itself as a massive and important contribution to the people of South Australia."

The NRAH is the single largest infrastructure project in SA's history but has been riven by industrial disputes and safety incidents, including the death of two workers.

There has also been a number of issues with its construction, including the recent emergence of problems with the hospital's hot water systems, which could cost up to $50 million and take months to fix.

In response to questioning from Opposition Leader Steven Marshall, Mr Weatherill accused Liberal MPs of exaggerating problems associated with the hospital.

He said the nature of the public-private partnership contract meant most of the financial burden associated with delays had fallen to the facility's developers.

But neither he nor Auditor-General Andrew Richardson could say when the hospital would open.

Health Minister Jack Snelling in April issued the developers with a major default notice, putting pressure on them to come up with a firm date for a handover.

The consortium has since missed multiple deadlines for technical completion, making it unlikely that the hospital will accept patients until well into next year.

Mr Snelling has stressed that taxpayers will not be charged for payments to the developers until the government takes ownership of the hospital.

The opposition has raised fears the hospital may not open before next winter's flu season, placing further strain on staff and facilities at the ageing Royal Adelaide Hospital.