Students from two eastern Auckland high schools have been exposed to measles.
Macleans College confirmed one of its students had measles earlier this week and issued a warning to caregivers.
"You must keep your child at home, in quarantine until 16 August if your child has not been immunised," it said in a statement from the school's principal Steven Hargreaves.
Pakuranga College has also confirmed that one of its students has measles in an email to parents but it has not issued a blanket ban for all unimmunised students.
Principal Michael Williams said the school had been in touch with the families of all students who may have been in contact with the infected student.
"Those students who may have been in close contact with this person, (same class, tutor class, sports teams, etc.) may have been exposed to the virus and, if they have not been vaccinated, should be quarantined for a few days," he said in the email.
"It is likely there will be more cases over the coming weeks, so it is important that all students get vaccinated."