The Ministry of Education is ringing all schools to find out whether they could cope with teaching online if they have to close their buildings due to coronavirus.
A newsletter sent to principals today says ministry staff will ring schools over the next two days to check their capacity to cope.
A later update issued late on Monday advised schools to keep students at least 1.5 metres apart at assemblies, and to reconsider school camps unless they have the ability to isolate any student who becomes ill and have "personal protective equipment and the ability to clean hard surfaces".
Principals' Federation president Perry Rush said the advice on assemblies was "a bit of a nonsense" because students were in close contact with one another much of the time in schools. But he said schools should consider camps seriously.
"I think in this climate, schools will want to be prudent about that," he said.
A further 17 countries, including India, Brazil, Russia and the United States, have implemented localised school closures.
Prime Minister Jacinda Ardern said there were no plans at this stage to close NZ schools, given that other countries - including Taiwan - had contained Covid-19 well while keeping schools open.
She added that closing schools would see young people being in close contact with carers, including grandparents, and the elderly were more susceptible to catching Covid-19.
Ardern said there was no plan at this stage to cancel any school holidays.
The ministry update said individual schools might be closed.
"The most likely scenario is if a student or staff member is confirmed with Covid-19, Health may require a school to close for a day or two, to undertake tracking and tracing of close contacts," it said.
"A close contact is generally described as someone who was in near proximity (1.5 metres) of a person confirmed with the virus for 15 or more minutes. For those with compromised immunity that is 2 metres."
Rush said there was "no imminent threat of school closures".
"The virus is being managed, so this is the time to make sure we have good planning in place that caters for all of the eventualities," he said.
He said the ministry was working on possibly providing both digital and non-digital resources for schools to use with students during any physical school shutdown.
Another group was looking at how to minimise disruption for senior students studying for the National Certificate of Educational Achievement (NCEA).
NZ Educational Institute president Liam Rutherford said he expected that any closures in New Zealand would be localised.
"The virus seems to move in clumps, so it's more likely that where you have an intensity that you will see schools closed for a short period of time," he said.
"We have some genuinely isolated parts of the country where it's unlikely the coronavirus is going to get to."
He said other countries where schools had closed were providing educational programmes remotely, and many NZ schools were already well set up to communicate with students and families online.
"So I think, if we did come up with that [closing physical schools], schools would cope because it would be an extension of what good teaching and learning is already doing," he said.
Otago University public health professor Michael Baker said closing schools and public transport were part of the "standard plan" for containing pandemics, but they were "at the extreme end" because of their social and economic disruption - likely forcing many parents to stay home from work to look after children.
"It's taking people out of the workplace, and also what do all those kids do?" he said.
"They may hang around together. You have to think through all the consequences."
Although most people who have died from coronavirus so far have been elderly and very few children have been hospitalised, Baker said children "are infected just as much as adults but they have a much milder illness".
"It's early childhood and primary schools that may be particularly important - with secondary school the jury is out - because young children have very few symptoms, therefore normal testing and isolating cases doesn't work so well for young children," he said.
"School closures are very effective if you have an intense pandemic spread, but the timing is very important because they are so disruptive."