Major Collision Investigation Unit detectives are investigating a collision in Tyntynder yesterday evening.
Police spotted a motorcyclist travelling at high speed on the Murray Valley Highway, between Nyah West and Swan Hill, about 6.25pm.
The male rider evaded police and officers lost sight of the motorbike.
A short time later, it is understood the motorcyclist collided with a car at the intersection of Murray Valley Highway and Tyntynder Road.
The rider, a 20-year-old Nyah West man, was airlifted to hospital with life-threatening injuries.
The driver of the car, a 30-year-old Swan Hill man, was not injured and stopped at the scene.
Police are continuing to establish the exact cause of the collision and the investigation is ongoing.
Anyone who witnessed the collision, has dashcam/CCTV footage or information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au