Another person evacuated from the Diamond Princess cruise ship to Australia has tested positive for coronavirus, taking the number of confirmed cases to seven.

Key points: Two Victorians tested positive for coronavirus overnight on Friday at a quarantine facility in Darwin

Two Victorians tested positive for coronavirus overnight on Friday at a quarantine facility in Darwin A Queensland patient tested positive on Saturday

A Queensland patient tested positive on Saturday Authorities had been expecting evacuees to test positive

The person from Queensland will remain in isolation overnight, before being repatriated home by Queensland health on Sunday.

Health authorities confirmed two Victorians tested positive for COVID-19 last night after four people were diagnosed with the virus on Friday — a woman from SA, a man from WA and two people from Queensland .

Northern Territory chief medical officer Dianne Stephens said the two Victorians and two Queenslanders would be repatriated to their home states on Saturday.

"We will continue to screen every day and have that very precautionary approach to testing and ensuring that we are picking up early and isolating early anybody who is positive for COVID-19," Dr Stephens said.

On Friday a 24-year-old South Australian woman and 78-year-old West Australian man tested positive for coronavirus and were flown to their home states after displaying flu-like symptoms on arrival to Australia.

A total of 17 people who have shown mild respiratory symptoms have now been isolated and tested for coronavirus. ( ABC News )

Dr Stephens said three more potential coronavirus cases had been identified among the cruise ship passengers overnight.

"We do have three people who were identified overnight that will be screened [on Saturday] and tested," she said.

"We have screening occurring [on Saturday] morning and I expect that there may be more people put into isolation during the day, and we'll have firm numbers about the testing some time later [on Saturday] evening and report those again [on Sunday] morning."

An evacuation plane from Japan carrying 164 Australians who had been stranded on the coronavirus-hit Diamond Princess arrived in Darwin on Thursday, with evacuees locked down at a quarantine facility 30 kilometres south-east of Darwin's CBD.

The Diamond Princess evacuees will remain in quarantine at the facility along with the 266 evacuees from Wuhan, the coronavirus epicentre, who are scheduled to be released on Sunday.

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

Earlier, federal chief medical officer Brendan Murphy said authorities had been prepared for positive coronavirus cases from the evacuated cohort.

He also warned there could be more coronavirus cases among the cruise ship passengers.

Since arrival at [the quarantine facility], a total of 17 people who have shown mild respiratory symptoms have now been tested after being isolated," Mr Murphy said.

"Given the continued evidence the infection was spreading on board the Diamond Princess in recent days, the development of these positive cases after returning to Australia was not unexpected, despite all of the health screening conducted before departure, during the flight and on arrival at the facility."

In a press conference on Saturday morning Mr Murphy said the Australian Government's decision to impose a second period of quarantine — in addition to an initial two-week quarantine on the Diamond Princess — had been vindicated following the new confirmed coronavirus cases.

"We now feel very strongly that our plan to quarantine those people, even though many of them felt that they'd had 14 days of proper quarantine on the boat, was completely justified," he said.

"It does seem clear that there was some ongoing transmission of the virus on the boat in those past few days, as we've seen from those six people who have tested positive over the past two days."

Federal Health Minister Greg Hunt said the virus had been contained in Australia, with no new cases in the general population within the last week, and was slowing globally.

He said the number of coronavirus cases in the general population remained at 15.

"That has been stable for some weeks. Ten of those 15 cases have recovered and returned home," he said.

'They are all reasonably well'

Dr Stephens said the four coronavirus cases waiting to be repatriated on Saturday were stable and presenting only mild symptoms.

Australian passengers from the Diamond Princess board the Qantas evacuation flight in Japan. ( ABC News: Jake Sturmer )

"They are all reasonably well with a cough, sore throat, symptoms of a common cold essentially," she said.

She said it would be up to local health authorities to decide how to manage each patient following medical retrieval on Saturday.

"They are being repatriated to their home states and if any of them become more unwell they will be able to enter their home states' health system and be cared for there," she said.

"We are really protecting the Northern Territory health system from having to deal with anybody who gets very sick from COVID-19 infection and making sure our capacity to respond to Territorians is maintained throughout this process."

Northern Territory Health Minister Natasha Fyles reiterated anyone diagnosed with COVID-19 would be repatriated to their home state.

"It's really important for Territorians to know that their health and their safety is paramount through this that is why, unless someone is critically ill, they will go straight from the Howard Springs facility to the airport and back to their home state," she said.

Ms Fyles said the medevacs of a South Australian woman and West Australian man who tested positive for coronavirus on Friday went smoothly.

"[On Friday] we saw two successful flights taking people home that had been in Darwin from the Diamond Princess but had tested positive to the coronavirus. They were successfully taken back to their home jurisdiction," she said.

"They did not go to the Royal Darwin Hospital. They went straight from the quarantine facility at Howard Springs in an ambulance out to the airport and they are now home being cared for by their state jurisdiction."

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

Japan says passenger found to be infected after leaving ship

A passenger who got off the Diamond Princess after completing the cruise ship's quarantine this past week tested positive for the new virus on Saturday, becoming the first known case of infection among those released at the end of the ship's containment period, Japanese officials said.

The patient is a woman in her 60s from Tochigi prefecture, north of Tokyo, who was on the ship with her husband, Tochigi Governor, Tomikazu Fukuda, said at a televised news conference.

More than 77,000 people have been infected globally, in as many as 27 countries. ( AP: Kiichiro Sato )

The woman had tested negative for the virus on February 15, four days before she got off the ship with her husband, with neither showing any symptoms at the time.

The couple took a train home, officials said.

Despite strong doubts raised from inside and outside the country, Japanese health ministry officials have insisted that any passengers who completed the 14-day quarantine, tested negative for the virus and showed no symptoms had nearly zero risk of becoming a virus patient.

"I would like to urge the government to take more thorough preventive measures," Mr Fukuda said.

Some experts and former passengers have criticised the quarantine, saying anti-infection measures were inadequate.

Japan's health minister, Katsunobu Kato, said 23 passengers had been released from the Diamond Princess at the end of the quarantine without being tested for the virus due to procedural mistakes.

He said the 23 were tested before the quarantine began February 5, but were allowed to leave the ship on Wednesday and Thursday without being tested again.

Three of them had since tested negative, and most of the others had agreed to be tested, he said.

Mr Kato said officials had tracked all 23 passengers down and asked them to self-quarantine at home for 14 days.

"We deeply regret that there was an operational error," he said at a news conference. "We will examine what went wrong so we will not repeat the same mistake."

Japan has confirmed more than 760 cases of the new virus, including at least 634 from the Diamond Princess.

Quarantine nearly complete for Wuhan evacuees

Ms Fyles confirmed the 266 Australians evacuated from Wuhan to the quarantine facility at Howard Springs earlier in the month would be sent home on Sunday.

Ms Fyles (left) has said those in quarantine will remain isolated from Territorians until they are repatriated. ( ABC News: Sowaibah Hanifie )

Arriving on the third and last flight to take Australians out of Wuhan, the cohort were scheduled for 14 days' quarantine at the facility.

No Australians in the cohort tested positive for coronavirus.

"[On Sunday] the Wuhan evacuees that came in two weeks ago [will be] able to be repatriated home to their home states, bringing to the end for them what has certainly been a holiday they won't forget in a hurry," Ms Fyles said.