Hume Crime Investigation Unit detectives are investigating a road rage incident in Craigieburn this morning.
Police have been told two male drivers pulled over on Hume Freeway between Craigieburn and Donnybrook roads about 8.15am.
The two confronted each other and then the unknown driver of the silver Holden Astra stabbed the driver of the blue Holden Calais before returning to his car and driving north on the Hume Freeway.
The victim was treated for non-life threatening injuries.
The offender is perceived as being of Middle Eastern appearance, aged in his mid- 30s, approximately 175cm tall, solid build, short dark hair and short beard.
He was wearing a white t-shirt, blue shorts and black boots.
Anyone who may have witnessed the incident or with any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report online at www.crimestoppersvic.com.au