The use of city hotels to keep returning Australians isolated during the COVID-19 pandemic has come in for criticism recently after a cluster of cases in Adelaide was linked back to one facility.

A cleaner at the hotel picked up the virus and spread it to other members of her family.

Opposition Leader Peter Malinauskas says with the number of coronavirus cases surging overseas, the number of infections among returned travellers has also increased.

"Continuing to accept international arrivals and putting them in CBD medi-hotels staffed by casual labour puts our state at greater risk of another outbreak," Mr Malinauskas said.

"This level of risk is simply unacceptable.

"The only way to alleviate this risk is the immediate and indefinite end of the medi-hotel system in its current format until a safer solution is found."

But Premier Steven Marshall said other ideas, such as sending returned travellers to places like Christmas Island, was logistically impractical.

As the so-called Parafield cluster emerged in Adelaide last week, the state government did put overseas flights on hold until at least December.

On Sunday, SA had 37 active cases of COVID-19 but only 11 of those were returned travellers in hotel quarantine.

Australian Associated Press