NSW Health has issued a warning against "false and misleading rumours, posts on social media and inaccurate reports" regarding the spread of coronavirus.

The top five myths about coronavirus have been dispelled by NSW Health which says garlic and sesame oil won't stop people contracting the virus and it can't be caught from imported food or domestic pets.

NSW Health on Thursday urged the public to be wary of incorrect and alarmist social media posts regarding the spread and severity of the disease.

"I ask the public to be aware of the facts about the novel coronavirus and take a moment to investigate unverified claims before they share them with others," chief health officer Dr Kerry Chant said in a statement.

A common myth about the virus is that people should avoid Chinatown and shopping centres or suburbs with high Chinese-Australian populations.

"While four cases have been diagnosed in NSW to date, patients have been isolated until no longer infectious and there is no evidence that community transmission is occurring," the state's health department said in a statement.

It is also not true that people can catch the coronavirus from imported packaged food.

"The novel coronavirus does not appear to last very long on surfaces ... therefore imported products do not pose a risk of transmission," NSW Health said.

Any suggestion that garlic and sesame oil will stop people contracting coronavirus is also "false".

Instead, people should practice good hygiene, as with any respiratory infection, the health department advises.

People should cover their nose and mouth when coughing or sneezing, always clean their hands thoroughly and avoid close contact with anyone with cold or flu-like symptoms.

NSW Health confirmed the World Health Organisation had debunked another myth - that the virus had mutated into a more lethal strain.

Any suggestion that coronavirus could be caught from pets is also false.

"While the 2019-nCoV may have come from animals, domestic pets do not pose a risk of transmission in Australia," NSW Health said.

Dr Chant says the novel coronavirus "appears to be less severe than SARS or MERS and many with the disease may have a mild illness".

The four confirmed cases of coronavirus in NSW were isolated after diagnosis and they do not pose an ongoing threat.

So far the virus has infected 28,000 people globally and there have been 563 confirmed deaths, with the vast majority of infections and deaths in China.