Western Australia is again on COVID-19 alert after a ship arrived in waters off Perth, with three symptomatic crew members set to be hospitalised.
The Darya Krishna bulk carrier will berth at Fremantle Port on Monday to allow for the emergency medical evacuation.
WA Health says three people will be transferred to Fiona Stanley Hospital by St John Ambulance via a dedicated COVID-19 vehicle and special operations staff.
The remaining 17 crew members will undergo testing at the port under strict protocols.
Premier Mark McGowan says eight of the crew are reported to be showing flu-like symptoms, including the second officer who he described as being "incredibly unwell".
They are suspected to have acquired the virus when the Darya Krishna docked in the Indonesian port of Batam on its way to Australia.
It has prompted the WA premier to issue a warning to shipping companies to tighten their protocols.
"We'll turn away ships if we can," he told reporters.
"It may be a bit hard with this particular ship because of the number of people who are unwell but if we can, we'll turn them away and that sends a message to the shipping companies: you will lose money if you don't deal with this situation."
Mr McGowan said it was hoped most of the crew members could remain on board to prevent the risk of infection in the community.
The Darya Krishna left Singapore on July 18 and had been bound for the port of Kwinana, south of the CBD.
Indonesia is in the midst of a coronavirus outbreak that has so far resulted in more than 1500 deaths since it began some weeks ago. The total number of infections is more than 3.1 million.
Last week, 10 crew members of another vessel - the BBC California - tested positive for the Delta strain of the virus after the cargo ship docked in Fremantle.
Eight infected crew remain aboard the ship, which had also visited ports in Indonesia before docking in Fremantle.
Another vessel that recently visited Indonesia, the Mattina container ship, has also had an outbreak after departing Fremantle bound for New Zealand.
None of the local ship workers who had contact with the vessel were infected.
It was agreed at Friday's national cabinet meeting that state and federal transport ministers will examine what can be done to prevent visiting ships arriving with infected crew.
"My view is when the ships are in Indonesia, the crew stay on board. They don't get off," Mr McGowan said.
"When you get off and you go to some of the port towns, the likelihood is you will catch COVID.
"It will be hard for the Indonesian government, I accept, to make this a priority at this point in time. It's up to the companies to do their job."
WA's borders remain closed to NSW, Victoria, Queensland and South Australia as they deal with their own Delta outbreaks.
The state reported no new cases on Monday.
