A student at Avondale College in Auckland has tested positive for Covid-19.
The school's principal Lyndy Watkinson said she was notified of the case last yesterday afternoon.
In a notice on the school's website, Ms Watkinson said she had been in touch with the student and their family who were "doing fine".
"Close contacts of the student have already received an email from me. Others in our school community are considered casual contacts.
"The College will continue to work closely with government departments over coming days."
A letter to parents, caregivers and staff of the school from the Auckland Regional Public Health Service outlined a 14-day isolation period for students and staff who have been in the same classes as the infected student.
"There will be a great deal of concern in the school community, but there is a lower risk as the student was not symptomatic while at school. They got tested when they felt sick and are now in isolation," the letter says.
"The school remains open for students and families who need to attend, particularly children of essential workers."
Glamorgan School in North Shore's Torbay closed last week after a students tested positive for the virus.
Southern Cross Campus and Taeaofou | Puaseisei Preschool, both located in South Auckland's Mangere East, also closed after positive cases were reported there.
Meanwhile, a student at Mount Albert Grammar School, who was linked to the South Auckland cluster, also tested positive last week.