Detective Senior Constable Wayne Ryan, of the Warrnambool police crime investigation unit, said someone must have seen something when the incident happened on the middle of Tooram Road between 2.45pm and 3pm last Saturday.

"People frequently use that road. We are asking that anyone who saw something contact the Warrnambool police station or Crime Stoppers on 1800 333 000," he said.

The driver suffered wounds to his neck and stomach after being attacked on when he was flagged down near Allansford.

He was travelling to Warrnambool from Allansford along Tooram Road just before 3pm.

The driver was flagged down by one man, they spoke and the offender produced a knife.

He demanded cash and that the victim hand over an unusual ring he was wearing. 

The victim got out of car and there was altercation with that male, during which the victim suffered stab wounds to his throat and stomach.

 A second man has then come from the side of the road and said: 'that's enough, let's go," 

About the same time a white utility approached the scene from Allansford and turned into Morgans Road.

Police want to speak to the driver of the utility.

Detective Senior Constable Ryan said the male offender was distinctively short, only 160cms high, in his mid to late 20s, of medium build, caucasian, wearing a black beanie and jumper and the skin around his eyes was dark and his eyes were sunken.

 He said it was a shocking crime committed on a victim who was only trying to help. 

The offenders eventually ran off and the victim drove himself to the Warrnambool police station to report the incident.

An ambulance was called and the man was conveyed to the Warrnambool Base Hospital where he received treatment, including stitches.

It's understood the man's neck wound was only millimeters from a main artery and he has been described as extremely lucky to have survived.