Currently, only those who have travelled, been in close case contact, have links to clusters or are health care workers can be tested, making it the most restrictive regime nationally.

The opposition urged the state government to conduct more tests with their health spokesman Chris Picton saying anyone who presents at a coronavirus clinic with symptoms should be tested.

"Other jurisdictions are expanding their testing now the decline on international and interstate travel has freed up resources - we should be doing the same," Mr Picton said.

"Identifying cases early is the best way to ensure people and their close contacts can be isolated, and prevent spread of the disease."

SA chief health officer Nicola Spurrier is considering widening the criteria due to the low increase of cases.

Professor Spurrier may open up the state's testing criteria for COVID-19 after just two new cases on Tuesday.

The state's total confirmed cases is 433.

While the state is in a good position to expand testing, Professor Spurrier wants to get on top of checking 750 Qantas staff who could be linked to a cluster of cases at Adelaide Airport.

About 150 of those workers have been tested so far, with the rest to be swabbed in the next 24 hours.

Meanwhile, an intensive care nurse at the Royal Adelaide Hospital is self-isolating after testing positive to COVID-19 after treating patients.

Executive Director of Nursing Rebecca Badcock said the nurse had been using the appropriate protective equipment when she contracted it.

"We are looking into the full circumstances surrounding this incident and this case," she said.

More than 20 hospital staff are in self-isolation as a result.

Australian Associated Press