One of the Australians diagnosed with coronavirus is in a serious condition, Prime Minister Scott Morrison confirmed on Friday.

Mr Morrison told Sydney radio 2GB that there were 15 cases of the potentially deadly virus in Australia, and a further eight from the Diamond Princess cruise.

“One of these is in a more serious condition in WA, we learnt today,” he said.

“But in the rest of the community we can go about our business.”

The man and his wife were among 164 Australians evacuated from the Diamond Princess. WA Today reported late on Friday afternoon that the 78-year-old man’s wife had also tested positive to COVID-19, after earlier testing negative.

WA media say the husband has been moved to intensive care at Sir Charles Gairdner Hospital in Perth. Hospital staff say he is in a serious but stable condition and was moved as a precaution.

No Australians have yet died from COVID-19.

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Confirmation of the WA man’s condition came just hours after the Prime Minister activated an emergency response plan to handle an anticipated pandemic – making Australia the first country in the world to go to emergency footing.

So far, 23 Australians have been diagnosed with coronavirus. But health authorities are bracing for a much wider outbreak as the lethal virus wreaks havoc across the world. 

State and territory health ministers met in Melbourne on Friday to thrash out the details of the pandemic plan.

It will include sweeping powers for governments if an outbreak occurs, such as shutting schools, isolating aged-care facilities and an economic stimulus package. It will also allow authorities to stockpile medicines and hospitals to set up special containment wards.

Federal Health Minister Greg Hunt said elderly people with weak immune systems remained at greatest risk from COVID-19.

Mr Hunt also urged people not to stock up on face masks – as many of the supplies came from China, which is still the subject of travel bans.

Greg Hunt and Brendan Murphy in Canberra on Friday. Photo: AAP

“We’re working on the rings-of-containment approach,” he said on Friday afternoon.

The country has about 20 million masks in its national medical stockpile, Mr Hunt said.

Nonetheless, “no one should go around wearing and wasting face masks”, chief medical officer professor Brendan Murphy said.

“While we are preparing and we are realistic about what might come in the future weeks, we are not in a situation where anyone needs to be concerned,” he said.

Dr Murphy said it was “very likely” more cases of COVID-19 would start to emerge in Australia in coming weeks. The emergency response plan was a way for health authorities “to be prepared for all eventualities”.

“We are not wanting the community to panic,” he said.

Friday’s COAG meeting of health ministers came as the World Health Organisation said the coronavirus outbreak had reached a “decisive point” and urged countries to redouble efforts to contain its spread.

The virus now affects 47 countries, has killed more than 2800 people and infected more than 82,500.

Nigeria confirmed its first case of COVID-19 on Friday – the first in sub-Saharan Africa. New Zealand also confirmed its first case.

Under Australia’s pandemic response plan, travellers will face extra measures at airports and ports to test to potential symptoms of the deadly virus.

“As this spreads we are going to have to monitor the hotspots around the world for coronavirus and overlay that with travel patterns,” Australian Border Force commissioner Michael Outram told Sky News.

“It’s hard to travel directly to Australia so that gives us some choke points that we can focus on.”

 -with AAP