The Auckland Regional Public Health Service says there are signs that a measles outbreak is spreading further in Auckland.
The number of confirmed cases of the viral infection has risen to 26, with most linked to a pupil from Oratia Primary School, in West Auckland.
The student, who wasn't immunised, developed measles when returning from Britain through Singapore, and was exposed to other children at the school.
Richard Hoskins, a Medical Officer of Health, says it's important that people check to see whether they are up to date with their immunisations.
Dr Hoskins says the public health service has advised quarantine for students at Epsom Girls Grammar School and AGC Parnell College.