NSW Health Minister Brad Hazzard said authorities did not know whether her death had been connected to the virus, but she and another resident at the home had had respiratory symptoms.

The worker, now in hospital, had worked for more than two decade at Dorothy Henderson Lodge, run by Baptist Care. She had become sick about February 24 but had not travelled overseas and had no known connection with coronavirus cases. Eleven residents at the home had now been isolated.

The aged care home is one of two Sydney flashpoints in the coronavirus crisis.

Work is also underway to track and isolate medical workers and patients in contact with a doctor at Ryde Hospital who also tested positive this week. NSW Health said 13 doctors, 23 nurses and four other health workers were in home isolation. Eighteen patients had been contacted to date, with 19 more patients still being tracked down.

Like the aged care worker, he had not travelled overseas and had no known contacts with infected people.

"So, we're certainly looking at how we can step up the testing that goes on with people presenting with respiratory conditions, that in the normal course might have been not be considered for corona," Mr Hazzard said.

As the virus takes hold, Professor Murphy foreshadowed new restrictions on fly-in fly-out workers to protect Indigenous communities.

"In isolated communities this infection could have pretty devastating consequences," he said.

More advanced protection was likely in those areas, especially for fly-in fly-out workers, who presented a particular risk to the communities and who were likely to face screening and changed staffing arrangements. A plan would be in place in the next fortnight, he said.

Professor Murphy revealed that Australia doesn't have sufficient personal protective equipment - masks and other equipment - for a worst-case coronavirus outbreak, but he said authorities were working to buy more and explore whether equipment could be manufactured in Australia.

And he criticised as "unhelpful" the modelling of the Australian National University's Warwick McKibbin, showing the potential for 96,000 Australian deaths in a worst-case pandemic, with 15 million deaths globally in the first year.

One hundred thousand Australian deaths was "a very extreme scenario", Professor Murphy said.

"It potentially is alarmist to start talking in those terms. Even in China we haven't seen an attack rate that's very high.

"Whilst theoretically you could have an outbreak of that nature, the assumptions you have to make to get to that level of severity I think are unhelpful."

Australia could be facing outbreaks of "moderate significance", but was well prepared to manage them, including very advanced critical care and access to heart and lung machines, which would mean a lower death rate than in some other countries.

"Presenting a number of emotive and dramatic worst-case scenarios doesn't do anything to help," he said.

A blood test was about to be released to identify the virus through blood tests, which would give a much more accurate picture of how many people had been exposed, including mild cases which had shown few or no symptoms, he said.

Professor Murphy said the actual number of cases in places like Hubei and China could easily be two or three times the number reported because the disease had gone undetected in Iran for some time, and in Hubei mild cases were unlikely to be presenting to doctors. The blood test would show who had been exposed and would the the only way to build an accurate picture of the size of the outbreak and the real death rate.

In Australia, tests were only done in public laboratories at the moment, but he was looking at extending that to private laboratories.

Professor Murphy said in a severe outbreak, elective surgery around the country would be cancelled, and he said it would be sensible for hospitals to bring forward elective surgery now if they had capacity. Queensland is bringing forward elective surgery and other states were looking at it, he said.