Education officials are advising students and teachers who've travelled to China and are at risk of contracting the deadly coronavirus to stay away from school for 14 days.

An edict was sent to all New Zealand principals last night by Education Ministry head Iona Holsted as fears over the escalating global outbreak grow.

"This is a new virus and its specific nature is currently unclear, however it appears that you can have the virus at an early stage and not be showing any symptoms," she said.

"This incubation period is currently considered to be 14 days."

Anyone who was at "high risk of exposure because they have recently been to China or have been in close contact with someone confirmed with the virus" should to stay away from school for two weeks, Holsted said.

"As always anyone who is unwell should not be at school or at their early learning service. If you have a particular concern about any child, student or staff member, please urge parents to contact Healthline at 0800 611 116 or their GP for medical advice.

"If a student still attends school while showing symptoms the principal of a state school can preclude them if they believe on reasonable grounds they may have a communicable disease."

Point Chevalier School wrote to parents today advising them of the Education Ministry's advice and asking anyone who had just arrived back from China or been in contact wh anyone confirmed with the virus to delay their child's start to school by 14 days.

"We are monitoring the situation in China closely with regards to the concerns around a potentially pandemic virus. We have procedures in place for the incidence of infectious diseases, and we will be revisiting them with our staff before classes return on Thursday.

"We are monitoring the Ministry of Health, Ministry of Education, and Safe Travel NZ sites to ensure we have access to the most up-to-date information and advisories."

Epsom Girls Grammar School has issued a similar message today.

"If you have arrived back in New Zealand from China in the last two weeks, or if you have travelled to an area of the world where the virus is now present and you feel that you may have been in contact with someone who has contracted the virus, we ask that your daughter does not come to school until you have been back in New Zealand for a period of two weeks (14 days). If everyone living in your household is symptom free, when the two week period is up, your daughter should then come to school as normal."

Meanwhile, a company running hostels for overseas students is calling for blood tests at the airports for everyone arriving from Asia who may have been infected by China's deadly coronavirus.

John Chen, who runs three buildings for 1200 mostly Asian students in Auckland, has written to MPs saying he cannot risk letting any student stay in his apartments if they show any symptoms of the virus, which has killed 80 people in China so far.

"A procedure must be set up that all tourists and students from China [have] to have blood tests, as soon as they arrive, [and] if they test positive they need to be quarantined in hospital immediately," he said.

"The virus is highly contagious and transmitted human to human. That will cause an epidemic in the buildings and our staff are not trained medically to deal with the situation."

New Zealand has about 35,000 Chinese students. Many have either just arrived for the new academic year or will return from holidays in China in the next few weeks.

Public health staff began meeting flights from China on Monday to check the temperature of anyone who feels unwell, but Chen said the Auckland Regional Public Health Service had told him that any students suffering from an illness with respiratory symptoms should "isolate themselves".

He said it was "ridiculous" to expect students to be quarantined in student hostels or homestays.

"We are not hospitals. We don't have the staff or the facilities. We are not specialists in containment," he said. "It should be done at the gate, at the airport."

His call came as Auckland's St Cuthbert's College wrote to students asking them to stay away from school for the next week if they have travelled to any infected country.

Apart from China, cases have been reported in Thailand, Taiwan, Japan, Singapore, South Korea, Vietnam, the United States, France, Australia, Malaysia, Nepal and Canada.

Passengers from parts or all of China are being heat-screened to look for high temperatures at major airports such as New York, Bangkok, Singapore and Dubai.

Rotorua's John Paul College principal Patrick Walsh, who chairs the Schools International Education Business Association (Sieba), said he had talked with five or six other principals who planned to follow St Cuthbert's lead and ask students from affected countries to stay away for at least a week.

Auckland Regional Public Health Service (ARPHS) director Dr William Rainger said public health officials were not yet heat-testing people at the airports.

"We are asking people to self-identify if they have any of the three main coronavirus symptoms at international arrivals (fever, cough or difficulty breathing) and a public health nurse will take their temperature if they report any of these symptoms," he said.

"ARPHS is ensuring all travellers from China know what to do if they are unwell, and where to seek medical advice.

"Standard illness advice to anyone who is sick, especially with respiratory symptoms, is that they should stay away from other people. This may mean staying in their room, away from other people as much as possible.

"Novel coronavirus is not as infectious as measles, the risk of transmission is more like that of flu."

A Ministry of Health spokeswoman said NZ laboratories should be ready to test for the coronavirus by the end of this week, but they would not be blood tests.

"In most cases, diagnosis will be from nose, throat and nasopharyngeal swabs, not blood tests," she said.

National education spokeswoman Nikki Kaye has asked Education Minister Chris Hipkins and Health Minister David Clark for an urgent briefing on what is being done to prevent infection from international students.

Otago University public health professor Michael Baker said experts were still assessing the nature of the coronavirus, but noted that British expert Professor Neil Ferguson had estimated that 100,000 people may already be infected.

"This is really going to be a very difficult epidemic to control, and that means that any risk assessment for New Zealand has got to start taking account of what this epidemic is doing in China and its potential to spread elsewhere," he said.

"There is no room for complacency whatever in New Zealand about this."