South Australia has announced a sweeping shake-up of its hotel quarantine, after tracing the origins of its troubling Parafield COVID outbreak to a security guard working in the program.

So far 29 coronavirus cases have been linked to the cluster, which sparked a brief lockdown across SA last week.

Health authorities initially thought a cleaner at the Peppers Hotel in the Adelaide CBD contracted the virus from a returned traveller.

But chief public health officer Nicola Spurrier said further investigations had determined that a security guard was the first person infected.

In a further development, Professor Spurrier said an examination of CCTV footage from the hotel had found no breach of safety protocols by staff.

“I can absolutely confirm that nobody was in the wrong place at the wrong time and I think that is the most important thing,” she said.

Tweet from @Staceylee_

SA authorities locked down the whole state last week, after initially suspecting the outbreak was a particularly virulent strain that had been spread even through contact on takeaway food packaging.

The lockdown was lifted after just a day and a half when a hotel security guard admitted he had lied – and was a worker in a pizza bar at the centre of the cluster, not just a customer.

He is now the subject of a police inquiry.

But the outbreak also sparked a review of the state’s hotel quarantine. On Wednesday, SA Premier Steven Marshall announced a host of changes, including that anyone who tested positive while in a medi-hotel would be moved to a dedicated health facility.

• Push to reform hotel quarantine, but premiers remain sceptical
• Quarantine must improve to deal with global virus spike – experts

Security at that facility – likely to be at Adelaide’s old Wakefield Hospital – will be provided by police. Staff will be forbidden from working in other high-risk locations, including prisons and aged care centres.

They will also be allowed to use dedicated hotel facilities in Adelaide to avoid returning to their homes between shifts.

Mr Marshall said he would also ask national cabinet to consider testing all Australians returning from overseas before they were allowed to board their flights.

He said a negative test would be required before they were permitted to travel.

Mr Marshall said SA remained committed to playing its part in the repatriation process and would resume international flights when it was safe to do so, although probably at lower numbers than in recent weeks.

He said while no system could eliminate all risk, the government would do whatever it could to make quarantine arrangements safer.

“We continue to act swiftly and decisively based on the expert health advice,” Mr Marshall said.

No new COVID-19 cases were reported in SA on Wednesday with 9403 tests conducted on Tuesday.

The Parafield cluster grew by two on Tuesday, with confirmation of infections in a couple in hotel quarantine. They were initially thought to have contracted the virus overseas, but in fact contracted it during their stay at Peppers.

Mr Marshall said SA remained on course to ease COVID-19 restrictions from December 1.

The state’s border restrictions with Victoria are likely to also be lifted then.

“We are hopeful, if there is no spike in the number of cases, that we are on track to go back to where we were prior to the Parafield cluster,” he said.

-with AAP