No new coronavirus cases have been detected in Western Australia after more than 50 people were ordered to isolate in the state's mid-west.
Twenty-five staff, 18 patients and eight visitors at Geraldton Hospital must quarantine until they return negative tests.
It comes after an infected ship crewman spent up to three hours in the emergency department before being moved to a negative pressure room.
The man in his 50s was airlifted to Perth and remains in a stable condition in intensive care at Sir Charles Gairdner Hospital.
Staff, patients and visitors in the ED were initially told they would not have to isolate.
That decision was reversed on Thursday following a meeting between government and health officials, despite Premier Mark McGowan describing the risk of transmission as "minuscule".
Upon returning a negative test, staff members will be allowed to return to work but must wear face masks at all times.
They will also undergo daily saliva tests.
Mr McGowan said the crewman "probably would have died" if his ship, which has since departed, hadn't been allowed to unload him for treatment at Geraldton.
A separate staff member at the hospital is required to quarantine for 14 days after entering a lift used by the infected crewman.
The hospital worker wasn't involved in the patient's transfer but had inadvertently used the lift before it had been appropriately cleaned. They were not wearing personal protective equipment.
Authorities say the vaccinated staff member was sent home to isolate immediately and didn't have any contact with the community.
The state opposition has questioned why the crewman was not immediately placed into isolation, blaming the government for failing to implement proper safeguards at regional hospitals.
Mr McGowan said protocols would be reviewed at all major regional health centres.
The crewman was hospitalised in Geraldton, 420km north of Perth, after falling ill while aboard an empty bulk carrier over the weekend.
The MV Emerald Indah has since departed for Indonesia after being blocked from docking near Perth.
