The Prime Minister says the coronavirus situation is "evolving" in Australia as passengers arriving into the country from Wuhan City in China are being met by biosecurity screening.

It comes as a Brisbane man thought to have contracted the potentially deadly coronavirus has been released from isolation, with doctors confirming he is no longer displaying any symptoms.

Scott Morrison said Australia's National Incident Response Centre is now activated and DFAT has raised its level of travel advisory into the area.

"I'm advised by the Chief Medical Officer the risk of transmission in Australia remains low, however the situation is evolving," Mr Morrison tweeted.

"Our National Incident Response Centre has been activated and is helping coordinate our response with Commonwealth medical experts working together with states and territories.

"We have the best health system in the world and we are prepared to deal with this situation. While Australians should remain alert, they should not be alarmed.

The coronavirus as seen under a microscope. (British Health Protection Agency)

Earlier, Australia's Chief Medical Officer Brendan Murphy told Today the Brisbane man being tested for the virus is "well"

The man who was placed in isolation at his home flew into Brisbane earlier in January after visiting family in Wuhan, where the virus broke out in December.

"What I've been told is that the tests aren't back yet, but that the person is well and is now at home in home quarantine, awaiting for the tests," Mr Murphy said.

"But the good news is that there's no clinical concern about this person but we still don't know whether they've had this virus or just another virus such as flu."

There are three flights a week from Wuhan into Sydney and each of these flights will be met by biosecurity staff.

Information will be displayed across all other points of entry into Australia to warn people who develop symptoms to seek urgent medical attention.

NSW Health announced it will assist commonwealth biosecurity staff at Sydney Airport to monitor those returning from Wuhan.

No cases of the novel coronavirus have been detected in NSW, the department said.

Mr Murphy said there is a number of reasons why Australian authorities are concerns about the spread of the virus.

"That there have been significant increases in case numbers in Wuhan in China, where the disease originated.

"We now have evidence of some human to human transmission which we didn't have before. And whilst there are many mild cases, there have been some serious cases and as we've heard this morning, reports of up to six deaths.

"So for that reason, we have in Australia instituted proportionate border measures in relation to direct flights to Wuhan but I should say that we are very well prepared as a nation to deal with any case of any of this disease if it does come here from China."

Health workers in the state's public hospitals, as well as community-based GPs, have also been given precautionary advice and the department has made novel coronavirus 2019 a notifiable disease under law.

In the US, a man who returned to the Seattle area in the middle of last week after travelling to the Wuhan area, where the outbreak began, has been diagnosed with the condition.

The man, who is in his 30s, is in good condition at a hospital in Everett, outside Seattle.

He is not considered a threat to medical staff or the public, health officials said.

They said he had no symptoms when he arrived at the Seattle-Tacoma airport, but he contacted doctors on Sunday when he started feeling ill.

The US is the fifth country to report seeing the illness, following China, Thailand, Japan, and South Korea.

"One of the particular features of this virus is that nearly everyone has a fever," Mr Murphy said.

Travellers wear face masks as they walk outside of the Beijing Railway Station. China has reported a sharp rise in the number of people infected with a new coronavirus, including the first cases in the capital. (AP)

"But it is not distinguishable from the flu and it is flu season in China at the moment. That is why we are very much focusing our attention on those direct flights from Wuhan where there is a higher risk but again, people with - who are unwell who, come off a flight like that, are probably just as likely to not have this virus as something else.

"But that is why we have developed protocols for the bio security officers and the Public Health officers and the Public Health officers to try to determine whether the risk is significant."

NSW Director of Health Protection Dr Jeremy McNaulty told Today that anyone who may be experiencing symptoms should get assessed as soon as they start experiencing them.

"Fever, cough, shortness of breath, those sorts of respiratory symptom, call ahead so the doctor can prepare," he said.

"You don't want to be waiting around with other people in the waiting room.

Chinese authorities have confirmed a new strain of coronavirus that originated in the nation can be transmitted between humans. (AP)

"The doctor can then assess you and with discussion with experts in public health, do the right tests.

Last month, doctors began seeing the new type of viral pneumonia - fever, cough, difficulty breathing - in people who spent time at a food market in Wuhan.

More than 275 cases of the newly identified coronavirus have been confirmed in China, most of them in Wuhan, according to the World Health Organisation.