Moonee Ponds police are appealing for witnesses following a motorbike crash which occurred in Sunbury earlier in the week, Victoria Police say.
The crash happened on Reghon Drive just before 6pm on Tuesday, 8 May.
The motorcycle was the only vehicle involved in the crash with the rider receiving serious injuries.
The rider, who was allegedly riding a stolen black Kawasaki Ninja motorcycle, was assisted at the scene by a passer-by.
Investigators would like to speak to anyone who witnessed the crash or the passer-by who assisted the rider.
Anyone with information is urged to contact Crime Stoppers.