The man's case is now believed linked to the latest cluster of infections in Melbourne's North, which grew to nine on Tuesday.

Deputy Chief Public Health Officer Emily Kirkpatrick said it was important for there to be complete transparency in the operation of the hotel quarantine system.

"It's very, very important that we emphasise that hotel quarantine is a high-risk business and we have to make sure whatever reports we put out to the community have been verified and provide accurate information," she said.

"It absolutely will be made public. I would hope within the next 48 hours that we have some findings that we will be able to put out to the community."

Dr Kirkpatrick said while a number of people had likely travelled from Victoria to SA in recent days, raising the potential for local virus cases, the number who might have visited exposure sites in Melbourne was expected to be low.

Premier Steven Marshall said the government believed it had taken every precaution possible with the hotel quarantine system but if the report identified even tighter levels of protection they would be implemented immediately.

"This is going to be a very important report, but we want to get it right, not rushed," he said.

"I think we've been very open, very transparent on everything to do with COVID management since day one."

SA has also imposed fresh restrictions on people with exposure to key sites in Melbourne linked to the city's fresh COVID-19 cases, including travel bans and quarantine requirements.

Anyone who recently visited those sites and who is already in SA will need to self-isolate for 14 days and also get tested three times.

Others will be asked to get tested and self-isolate until they get a negative result.

South Australia reported one new coronavirus case on Tuesday, in a man in his 30s who recently returned from overseas.

The state has two active infections, both returned travellers in hotel quarantine.

Australian Associated Press