Mandatory, regular COVID-19 testing for workers in Adelaide’s quarantine hotels has come into force after a dangerous cluster of cases linked to a cleaner who passed the virus onto her family.

The direction that came into force on Wednesday requires police, SA Health officials, defence force personnel and all employees and contractors working in the quarantine hotels to be tested weekly.

It also covers all cleaning and security staff.

Any person working at a medi-hotel who develops coronavirus symptoms must notify SA Health for further directions about self-isolation.

People who deliver goods to the hotels through designated green zones and are on the site for less than half an hour are exempt, as long as they have no contact with people in quarantine.

The regulations follow confirmation last week that the so-called Parafield cluster in Adelaide’s north originated from the Peppers Hotel in Adelaide, when a cleaner became infected.

The cluster had reached 29 cases by Tuesday but authorities were confident it was under control.

Two more cases were added on Tuesday in unusual circumstances, prompting an investigation into how the virus was transmitted.

They were found in a husband and wife who recently returned to Australia and were thought to have contracted COVID-19 while overseas.

Their infections were revealed on Sunday and Tuesday.

Chief public health officer Nicola Spurrier said further genetic testing had revealed the couple became infected while in isolation in the Peppers Hotel.

South Australia went into lockdown for six days. Photo: AAP

Their cases have prompted SA Health to review CCTV footage and conduct other inquiries to work out how they contracted the virus, amid growing concerns for the security of the state’s hotel quarantine.

As a precaution, all hotel staff will also be tested again.

“We think that this is just being abundantly cautious. We don’t expect to have any more positives,” Professor Spurrier said.

“But what we do need to be absolutely sure about is that we’re not missing any further infection in that hotel system.”

Professor Spurrier said details of what happened at the hotel would be provided once the review was complete.

Earlier on Tuesday, authorities expressed continued optimism that South Australia remained on track to next week ease restrictions sparked by the outbreak.

SA’s transition committee will meet on Friday in what looms as a crucial gathering for local businesses and for families in the lead-up to Christmas.

If all goes well, SA will also lift its border restrictions with Victoria from December 1.

-AAP