WA teenager dies in motorcycle crash

A teenager has died and his 15-year-old cousin is in a serious condition in hospital after a head-on motorcycle crash south of Perth.

The boys were both riding dirt bikes near sand dunes in Wonnerup, east of Busselton, when they collided on Sunday afternoon.

One of the boys, 15, suffered severe head injuries in the crash, dying shortly after being taken to Busselton Hospital.

His cousin also suffered extensive injuries and is being treated at Royal Perth Hospital.

Police are investigating the crash and preparing a report for the coroner.