The virus has spread across the world, with five confirmed cases in Australia.

Foreign Minister Marise Payne said early on Wednesday morning travel restrictions were in place in China.

"Do not travel to Hubei Province. Contact your doctor for symptoms of respiratory illness," she urged.

Updated travel advice on the Smartraveller website advises Australians to "reconsider your need to travel" to China overall and "do not travel" to Hubei Province due to the outbreak of coronavirus.

"Chinese authorities have restricted travel for parts of the country and may extend these restrictions at short notice," the warning states.

"Travellers may be quarantined, due to their health condition or previous location.

"If you've travelled to Hubei Province and have developed symptoms of respiratory illness, contact your doctor."

If you or someone you know is in China and needs assistance, contact +61 2 6261 3305 from overseas or 1300 555 135 from within Australia.

The following information was issued by NSW Health on January 28, 2020.

Coronaviruses are a large family of viruses, some cause illness in humans, and others cause illness in animals, such as bats, camels, and civets. Human coronaviruses cause mild illness, such the common cold.

Rarely, animal coronaviruses can evolve to infect and spread among humans, causing severe diseases such as Severe Acute Respiratory Syndrome (SARS) which emerged in 2002, and Middle East Respiratory Syndrome (MERS) which emerged in 2012.

A novel coronavirus (2019-nCoV) is a new strain of coronavirus that has not been previously identified in humans.

There is a new coronavirus affecting people who have recently been in the city of Wuhan, China.

There is growing evidence that 2019-nCoV can spread from person to person in the community and in health care settings. There have been cases of 2019-nCoV reported in several Asian and other countries including Australia. The situation is evolving rapidly.

Most case-patients have had fever, cough, and shortness of breath, with further evidence of pneumonia (chest infection).

Further investigation is required to assess whether there are undetected asymptomatic or mildly symptomatic cases.

It is unknown how long symptoms take to present. At this stage, it is most likely between two and 14 days.

Early reports indicated that most of the cases had prior contact with a seafood and live animal market, suggesting an animal source of the outbreak. However, more recently, human to human transmission has been reported.

Further investigation is underway to confirm and describe the mode of transmission from animal sources, and the risk of human-to-human transmission.

Human to human transmission is most likely to be through direct contact with infectious patients, by respiratory droplets and by fomites (contaminated objects and surfaces), as is seen with other coronavirus infections including SARS and MERS.

People who are living or travelling to affected areas or who have had contact with other cases may be at risk of catching the disease.

People with underlying illnesses that make them more vulnerable to respiratory disease, including those with diabetes, chronic lung disease, pre-existing kidney failure, people with suppressed immune systems and the elderly may be at a higher risk.

It's likely that general prevention measures used for other coronavirus infections will also prevent infection with 2019-nCoV.

The World Health Organization (WHO) recommends measures to reduce the general risk of acute respiratory infections while travelling in or from affected areas by:

Travellers to China are already advised not to visit live bird and animal markets, including 'wet' markets, due to the risk of avian influenza.

There is currently no vaccine to prevent 2019-nCoV infections.

If you become ill or feel unwell while travelling in China, you should not wait until you arrive back in Australia to seek medical assistance. Instead you should see a doctor or go to the local emergency department.

If you develop a fever, a cough, sore throat or shortness of breath within 14 days of travel or have had contact with a person with confirmed coronavirus, you should immediately isolate yourself from other people. Contact your GP or your emergency department or call the healthdirect helpline 1800 022 222 and seek medical attention as soon as possible.

It is important to phone ahead so that the practice or emergency department can make appropriate preparations and protect others.

When seeking medical care wear a surgical mask (if possible) otherwise ask for one when you arrive.

Infection with 2019-nCoV is diagnosed by finding evidence of the virus in respiratory samples such as swabs from the throat or fluid from the lungs. Testing for 2019-nCoV is done in public health laboratories.

There is currently no specific treatment for people who are sick with 2019-nCoV but general supportive medical care in hospital can be life-saving.

As of January 23, 2020, in Australia procedures to prevent the local spread of 2019-nCoV have been put in place.

Public health unit staff will investigate all cases to find out how the infection occurred, identify other people at risk of infection, implement control measures and provide other advice.