Two children have been pulled from two Auckland high schools because a family member has contracted the Covid-19 coronavirus.
Ministry of Health director-general Ashley Bloomfield said a woman in her 30s has New Zealand's second confirmed case of the virus. She returned to Auckland from northern Italy last week on a flight via Singapore.
The two children who live with her attend Westlake Boys and Westlake Girls high schools.
Dr Bloomfield said it was highly unlikely they would have spread to the virus to other students.
"The students, one in each school, are not symptomatic. And as I've outlined, there's very clear data from China that people who don't have symptoms are not ones who spread the virus.
"The virus is spread through droplets spread by coughing and sneezing."
Dr Bloomfield said the woman's partner was now showing symptoms and was being tested for Covid-19.
Read more about the Covid-19 coronavirus:
- Covid-19: What it is and how to protect yourself
- Scientific hand-washing advice to avoid infection
- Second case of coronavirus confirmed in New Zealand
- Coronavirus patient 'never really felt unwell'
Westlake Boys High School principal David Ferguson said he was shocked to learn one of his students was related to the second person to be infected with coronavirus in Aotearoa.
The boy is in isolation at his home.
Parents were emailed at midday with the news, and Ferguson said a handful of students were taken home by parents afterwards.
He said there wasn't a rush to pick up students, but tomorrow could be a different story.
The boy's sister, who attends Westlake Girls High School, is also in isolation and no-one at that school is at risk either.
Education Minister Chris Hipkins said parents and students should rest assured that the schools had the situation in hand.
"They [the schools] are being well supported by the Ministry of Education, they have support from health officials if they need it. There is a very very low probability of it having transmitted at the school. Those two students concerned were showing no signs of having been infected, they have no symptoms."
Prime Minister Jacinda Ardern earlier sought to reassure the public about New Zealand's preparedness.
"What I want to provide reassurance around is that New Zealand has experienced these situations before, last was in 2009.
"We are equipped to deal with these situations, we have a plan that has been operationalised," she said.
She said good hygiene, staying home when unwell, washing hands did make a difference.
She said the case showed that not all Covid-19 cases would require hospital treatment.
"Self-isolation in these cases is, of course, one of the most effective things we can do to stop the spread of influenza-style illnesses ... there will be cases that will be mild-to-moderate and can be appropriately dealt with at home."