Officers from Melton Highway Patrol are appealing for information following a motorcycle crash in Melton yesterday.
It is believed a female rider was travelling north on Coburns Road, over the Western Freeway overpass, when she left the road about 3.15pm on 30 March.
The rider, a 44-year-old woman from Melton, was airlifted to hospital with life-threatening injuries.
Investigators believe there may have been another motorcycle involved in the collision are appealing for anyone with CCTV or dash cam footage to come forward.
It is believed the motorcycle failed to stop and continued north bound.
Anyone who witnessed the incident or with footage is urged to contact Crime Stoppers on 1800 333 000 or make a confidential report at www.crimestoppersvic.com.au