A doctor who is sleeping just four hours a night while working to diagnose possible coronavirus patients in Sydney says more severe cases in Australia are likely.

Key points: Ten scientists are testing samples to diagnose coronavirus cases in Sydney

Ten scientists are testing samples to diagnose coronavirus cases in Sydney Dr Jen Kok says there is still a lot to be learned from the virus

Dr Jen Kok says there is still a lot to be learned from the virus Australia is well prepared for a pandemic, scientist Dominic Dwyer says

The disease has killed 170 people and infected more than 7,500 in China, with seven cases confirmed and several others being tested in Australia.

Jen Kok, a medical virologist with NSW Health Pathology, is one of 10 experts working to diagnose cases at Westmead Hospital.

While most patients in NSW are currently stable, Dr Kok said it was likely more serious cases would develop.

"I think we will [see severe cases in Australia] but whether they go on to pass away or not, I can't comment on that," he said.

Dr Kok said the scientists were working round the clock to test samples.

"There's always excitement about a new pathogen or a new infectious disease but staff are very well trained," he said.

Dr Kok said he generally slept four hours every night, irrespective of whether there was a new virus.

"I don't expect attention for my work. I work in the shadows and I'd prefer to stay there."

Dominic Dwyer worked on the SARS and Avian Flu outbreaks. ( Supplied )

He said there were a lot of unknowns when it came to this strain.

"I think there's still a lot to be learned from this virus and we're getting more information coming every day," Dr Kok said.

"It is similar to previous coronaviruses, by that I mean the genetic sequence that they share particularly with SARS virus."

Director of Public Health Pathology at NSW Health, Dominic Dwyer is also testing positive samples at Westmead Hospital.

He said, for the most part, our health system was well prepared for a pandemic.

"We have a strong practice of infectious diseases here so I think the transmission of infections could be reasonably well managed.

"At this stage, our ability to quarantine small numbers of cases is very good."

But the situation could change if the number of cases explodes in Australia.

Passengers wear masks to prevent an outbreak of a new coronavirus. ( AP: Kin Cheung )

"If we had many more cases it would put a strain on the system but there are periods of stress in the hospital system from time to time," Professor Dwyer said.

"For example, in the middle of winter we're coping with hundreds of admissions to hospital each week for influenza."

A vaccination for the disease could be some time away but the trial of antiviral drugs, used to treat HIV, is underway.

"Other antivirals and other agents have been used [to treat other coronaviruses] but it would be hard to ascertain whether these agents are truly effective or not at the moment," Dr Kok said.

The Federal Government has significantly revised its advice about the virus, conceding human-to-human transmission can happen even if patients don't show symptoms of the disease.

"The issue we have is we may not detect those patients who are either asymptomatic or have very few symptoms," Dr Kok said.

"People who are asymptomatic or who may only have minor symptoms may not present to hospital."

One of Australia's worst flu seasons was in 2017, with more than 200,000 people diagnosed.

Professor Dwyer said much had been learned since then.

"We have been doing a lot of pandemic planning which has been going on back since the bird flu days and was tested in 2009 with swine flu," he said.

"This is not like Ebola virus — the numbers of deaths are still only around 100 out of 4,500 confirmed cases.

"But if the disease turned out to be as bad as Ebola virus, that's a different matter. No planning would necessarily help that."