People who visited Kelston Boys' High School recently have been warned to watch for symptoms of measles.
The Auckland Regional Public Health Service (APRHS) has been notified of a possible case of measles at the school and is advising anyone who visited between September 20-25 to be wary.
Measles usually begins with a high fever, runny nose, cough and sore red eyes, followed by a rash starting behind the ears and spreading to the body a few days later.
One in three people with measles will develop complications, such as ear infections, pneumonia, diarrhoea or, rarely, inflammation of the brain.
If people are infected they could begin experiencing symptoms from 7 -18 days after exposure.