Authorities have confirmed four people evacuated to Darwin from the Diamond Princess cruise ship have tested positive for coronavirus.

Key points: The four Australians will be medically evacuated to their home states after contracting coronavirus

The four Australians will be medically evacuated to their home states after contracting coronavirus They were aboard the coronavirus-hit Diamond Princess cruise ship

They were aboard the coronavirus-hit Diamond Princess cruise ship 164 people were evacuated from the cruise ship and taken to Darwin for a two-week quarantine period

On Friday night, two Queensland women aged 54 and 55 tested positive for the infection and will be flown to a Brisbane hospital for further treatment.

Earlier on Friday, a 24-year-old South Australian woman who tested positive for the virus was being flown from Darwin to Royal Adelaide Hospital to be held in isolation, health authorities said. A 78-year-old West Australian man also tested positive for coronavirus.

The South Australian woman tested negative for the virus in Yokohama before flying to Australia, but alerted health authorities of flu-like symptoms on her arrival in Darwin.

South Australia's chief public health officer Nicola Spurrier described the woman's "mild symptoms" as including a sore throat and runny nose.

"That was why she was tested and the results came back very promptly," Dr Spurrier said.

"[The flight] will be an RFDS flight [from Darwin] supported by nursing staff, and it will arrive at Adelaide airport and be met by an SAAS patrol, and she'll be taken to the Royal Adelaide Hospital for assessment.

"We'll make sure that she is isolated but we need to get her back and we just need to assess how she is and she'll be admitted at least in the first instance."

The confirmed cases come after six people were isolated after presenting minor symptoms on arrival at Darwin airport on Thursday morning.

The 164 people evacuated from the cruise ship will spend two weeks at a quarantine facility at Howard Springs, 30 kilometres south-east of Darwin's CBD.

Acting NT chief health officer Dianne Stephens said it was not likely the patients would be moved to Royal Darwin Hospital. ( ABC News )

The Australian Government's chief medical officer, Brendan Murphy, said authorities had been prepared for positive coronavirus cases from the evacuated cohort.

"Given there was continued evidence of spread of infection on board the Diamond Princess in recent days, the development of some positive cases after return to Australia is not unexpected, despite all of the health screening before departure," he said in a statement.

Professor Murphy said the first two infected Australians were stable and would be returned to their home states on medevac flights with appropriately trained staff onboard.

"[The first two patients] are in clinically reasonable condition, they're not unwell," he said.

Two Australians tested positive for the virus inside the Howard Springs quarantine facility. ( ABC News )

Professor Murphy said strong precautions were taken during the flight to Darwin.

"Passengers wore masks, practised good hand hygiene, the crew avoided contact with the passengers except from the AUSMAT health professional team who were very well trained and wore very good personal protective gear," he said.

Several buses transported passengers from the Diamond Princess to the airport. ( ABC: Jake Sturmer )

"Because of what's been happening over the last week in Japan and on the cruise ship, it's possible that more people could develop positive tests over the next few days.

"We don't know that but if they do we are completely well set up to detect and manage them and isolate them."

A plane from Japan carrying Australian evacuees who had been stranded on the coronavirus-riddled ship arrived in Darwin on Thursday morning, just hours before Japanese public broadcaster NHK announced two passengers who had been aboard the cruise ship had died.

"All passengers were health screened before being allowed to leave the ship, none had positive tests or any symptoms of disease," Mr Murphy said.

"They were monitored throughout the flight, screened again at the RAAF Base in Darwin and again on arrival at [Howard Springs].

"Six people were identified as having minor respiratory symptoms and/or fever. They were immediately separated from others at the airport and went directly into isolation at the village.

"Two of those people have since tested positive for COVID-19 infection."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 47 seconds 47 s Australian evacuees Trevor Overton and his partner leave the Diamond Princess to head to Darwin

As of Thursday, more than 621 passengers were infected on the ship, including 46 Australians.

The Australian Diamond Princess evacuees remain in quarantine at the disused workers' camp in Howard Springs, where they joined 266 evacuees who were evacuated from the coronavirus epicentre, Wuhan, a just over a week ago.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 24 seconds 24 s The Manigurr-ma camp outside Darwin is expected to be used for coronavirus evacuees

Health authorities had previously indicated any coronavirus cases would be treated at Royal Darwin Hospital, but acting Northern Territory chief health officer Dianne Stephens said the stable condition of the first two infected patients meant they could be returned home.

"So the natural progress of this disease is people slowly get worse, so we do not anticipate that the Royal Darwin Hospital will be involved with these two people at all," she said.

"Having said that, if someone does become ill and requires hospitalisation, our system remains ready to receive those people."

NT Health Minister Natasha Fyles moved to assure locals living around the quarantine facility of their safety, saying the isolation of the coronavirus patients and Diamond Princess evacuees meant any infection was contained.

"We know the coronavirus is droplet based, so people need to come into close direct contact [to contract the disease]," she said.

"Dr Stephens has made sure that the community of Howard Springs particularly is fully informed around what has been happening, but these people are in isolation.

"They have not come into contact with everyday Territorians. They came off that Qantas flight on the RAAF side of the terminal, and they were bussed out to that site in strict processes, isolating them from the broader Territory community [with] strict protocols around their hygiene.

"I can reassure the territory community that their health and safety is at the forefront."

Australian man Trevor Overton, who was evacuated from the Diamond Princess and is currently inside the quarantine facility, said the latest infections were "not a surprise" after what he saw on the cruise ship.

Trevor Overton (pictured) said rigorous hygiene standards were not adhered to on the Diamond Princess. ( Supplied: Trevor Overton )

"We've been through this ordeal for two weeks already. All of our lives have just stopped, but we have to remain positive," he said.

"It's not a surprise to me that some people have contracted the virus.

"When we were on the ship we saw passengers not following instructions, not wearing masks and smoking, for example. It's very difficult to control or monitor 3,800 people on a ship."