Detectives at Knox Criminal Investigation Unit are appealing for witnesses following an armed robbery at a supermarket in Ferntree Gully on Friday.
Police have been told a man entered the supermarket on Burwood Highway just after 9.30pm.
It is believed the man approached an attendant and produced a knife before demanding cash from the register.
The attendant handed over a significant amount of cash and the bandit fled the scene in a vehicle.
The offender is described as being Caucasian in appearance, aged 30 to 35-years-old, unshaven with a medium build.
He was last seen wearing a blue peaked cap, sunglasses, a long sleeved jacket, shorts and runners.
Detectives have released an image of a man that may assist with their enquiries.