A report has found human error was the likely reason a back-up power unit at an Adelaide hospital failed during last year's statewide blackout.

Human error has been blamed for the loss of embryos at a fertility clinic in Adelaide in September when an emergency generator failed during a statewide blackout.

An investigation found that a control switch on the generator's fuel system was wrongly left in the off position, leaving the state government open to possible compensation claims.

The embryos of 12 families held by Flinders Fertility at the Flinders Medical Centre were lost when the back-up power went down.

Health Minister Jack Snelling says he's sorry for their losses and has promised the government will be a model litigant in regard to any claims.

"It's extremely distressing that such a small error could have such a catastrophic outcome," Mr Snelling told reporters on Monday.

The report into the loss of power found only a small number of people had access to the generator but no one admitted leaving the switch on the fuel system turned off.

Maintenance work had only recently been completed and Mr Snelling said he was comfortable that the company contracted to perform that work would continue to do so into the future.

A generator at the Port Augusta Hospital also failed during the blackout when wild storms lashed SA and brought down major transmission lines, but a report into its overheating revealed it was more than 40 years old and had not been properly tested or maintained.

Mr Snelling said the government was in the process of having it replaced.