Premier Steven Marshall has flagged some changes within the next 24 hours as authorities look to impose measures that will prevent the disease getting into nursing homes.

They are considering ways to deal with the problem of staff working across multiple sites and also the mandatory use of masks.

The premier has also confirmed SA will continue with its policy of removing any nursing home residents who contract coronavirus and admitting them to hospital.

"We can't be complacent. We have got to constantly look at the restrictions that we have because we know that we have vulnerable communities in those high-density arrangements," Mr Marshall said on Wednesday.

"They have been very dangerous situations in other parts of the country."

The premier said the officials were working with aged care providers, residents and their families to introduce "logical" new restrictions to keep everyone safe.

"It would be very easy to close off every residential aged care facility in the state and let nobody in or out," he said.

"That would probably be the safest but what would the quality of life be?

"What we're trying to do is always balance up the risk with the restrictions."

SA is also looking at new measures to ensure COVID-19 restrictions in pubs and restaurants are followed more closely by having venues nominate staff responsible for ensuring the business and customers are doing the right thing.

"When everybody is essentially responsible, it sometimes means that nobody is responsible," Mr Marshall said.

"We need somebody to go to and check that COVID-safe plan and take action if we need to."

South Australian has just one cluster of five cases causing concern, which has been linked to an adult learning college in Adelaide.

But no new infections have been reported in the past three days.

Australian Associated Press