Parents are being urged to limit their children’s use of personal devices.
A youth hearing loss screening programme revealed as many as a third of year 9 students have abnormal hearing.
28 percent of students screened at Auckland's Manurewa College said they listened to music at maximum volume for more than three hours a day.
That's despite the World Health Organisation's recommendation of no more than six minutes a week at peak volume.
The Foundation for Deaf and Hard of Hearing's CEO Natasha Gallardo says parents and teachers need to help young people recognise the harm they might be doing.
LISTEN ABOVE AS NATASHA GALLARDO SPEAKS TO HEATHER DU PLESSIS-ALLAN