Schools are being told to prepare for closures of "several weeks" once swine flu takes hold in the community.
The Health Ministry wrote to schools last week in its campaign to explain to the public that despite containment of the disease so far in New Zealand, the country would soon be hit hard by the virus. This is because of the fast rising number of cases in Australia and the impossibility of detecting and isolating all cases at the border.
In New Zealand 14 people with A (H1N1) flu have been confirmed, all of whom had travelled overseas, but in Australia the tally has passed 600, including 521 in Victoria.
Ministry public health director Dr Mark Jacobs wrote that schools must prepare how they would cope when the virus - readily spread by children - started circulating freely.
"If a school or early childhood service was directed to close it could happen very fast - students would be sent home at the end of the day and told not to return. Your communication with parents needs to be thought through and prepared. Consideration also needs to be given to remote learning and lessons by schools, not just for a week, but potentially several weeks."
Secondary Principals' Association of New Zealand vice-president Paul Daley said closing schools for this long would disrupt learning, but if it was needed there could be no objection.
"If we get to that, everybody's health is what's important."
Some education could continue through email, the internet and by hand-delivering materials, but this had limitations. If some schools were closed for much longer than others, this would have to be taken into account in NCEA results.
Dr Jacobs also suggested students be kept home from school for a week if they had recently returned from Australia, even without flu symptoms.
This suggestion has caused confusion. The Ministry of Education told principals it was "background information for families and not a directive. Schools and early childhood education services are not expected to act on this suggestion".
Dr Jacobs' suggestion reflects a controversial move by New South Wales state to impose a seven-day quarantine period on children returning there from neighbouring Victoria. They cannot attend school for a week, which the Victorian Government called bizarre.
Mr Daley said the Ministry of Education's email had "clarified" Dr Jacobs' letter.
What action to take regarding asymptomatic pupils returning from Australia was up to each school, Mr Daley said. He advised principals to prevent such children from simply returning to school. He suggested they first be questioned by a school nurse about potential contact with flu patients before deciding the appropriate action.