Tourist, 38, is in a critical condition at Royal Perth Hospital after a bicycle crash on Rottnest Island

A tourist has been airlifted to hospital with life-threatening head injuries following a serious cycling accident on Rottnest Island.

Emergency services were called to Digby Drive in the Thompson Bay area at around 5pm on Tuesday following reports that an overseas visitor had fallen off his bike.

Police and staff from Rottnest Island Care Station arrived at the scene to find a 38-year-old woman with life-threatening head injuries.

The woman was transported off the island by RAC Rescue Helicopter and taken to Royal Perth Hospital, where her condition is described as critical.

Police said an investigation into the circumstances surrounding the crash is ongoing.