Four cases of the coronavirus have been confirmed on Saturday, one in Victoria and three in NSW.
Victorian health authorities confirmed the first case of novel coronavirus detected in a patient in Australia on Saturday morning and a further three cases were confirmed in NSW on Saturday afternoon.
The Victorian patient, a man in his 50s from China's affected Wuhan province, flew to Melbourne from Guangzhou on January 19 on a China Southern Airlines flight, flight number CZ321.
He visited a GP clinic on Thursday with symptoms of pneumonia before going to a hospital in Melbourne on Friday, where he was put into isolation immediately.
A positive test for coronavirus was returned on Saturday morning.
Australia's Chief Medical Officer, Professor Brendan Murphy, described the man as "very responsible", having called ahead to describe his symptoms and where he was from.
Professor Murphy said "about a dozen" people had tested negative to the virus in Australia, though this was an ever-evolving number and there were "probably in the order of half a dozen people having tests across the country today".
"In terms of the Australian public, unless you have been in close contact with someone who is unwell and who has come from that part of China, there is no need for current concern," Professor Murphy said.
"At this stage there is no risk to the general Australian community. I want to emphasise that, but clearly we are keeping a very close eye on this situation."
Professor Murphy said it was important people who had recently arrived in Australia from Wuhan, and those in close contact with them, watch for signs of the virus and call ahead before seeing a doctor.
"We don't know exactly how long symptoms take to show after a person has been infected, but there is an incubation period and some patients will have very mild symptoms," he said.
"Symptoms include fever, cough, sore throat, vomiting and difficulty breathing. Difficulty breathing is a sign of possible pneumonia and requires immediate medical attention."
On Saturday afternoon, NSW health minister Brad Hazard confirmed three cases of coronavirus had been identified in Sydney and those people had been isolated.
Four more people were being assessed for possible coronavirus infection.
China has confirmed 41 deaths from the virus, while more than 1000 people are now estimated to have been affected worldwide.
An ACT Health spokeswoman said there were no suspected cases in the ACT on Saturday.
"The ACT Health Directorate has well established processes and procedures in place for the management of infectious diseases should they occur in the ACT and is working in partnership with the Australian Government Department of Health and our jurisdictional counterparts to monitor and respond to the situation," the spokeswoman said.
"The ACT Health Directorate is also working closely with our public hospitals, as well as General Practitioners and other primary health care providers, to ensure relevant health workers have the information they need to identify cases and put appropriate infection control measures in place should the need arise."
Health Minister Greg Hunt said isolation facilities existed in each state and territory in Australia, and processes for identifying and treating the virus had now been activated.
"Our laboratories have developed testing processes for this novel coronavirus that can provide a level of certainty within a day," he said.
The Department of Foreign Affairs and Trade has raised the level of travel advice for the Wuhan and Hubei provinces in China to level 4, "do not travel", and has issued a smartraveller bulletin on the virus outbreak.
- For more information about the novel coronavirus, visit health.gov.au.