Maroondah Crime Investigation Unit detectives are investigating two incidents of deception committed in the Ringwood and the Melbourne CBD areas over the past two weeks.
The first incident occurred at a store in Ringwood on 13 May when a man entered the store and selected an item to purchase.
The man paid for the item with a $100 note and was given his change which he put in his pocket.
He then asked the attendant to change the denomination of the notes given to him in his change.
The attendant became confused and unwittingly gave the man an extra $45 following which he walked out of the store.
Later in the day the same man attended a store in Boronia and walked away with an extra $140 after again confusing the attendant over the amount of change he was given.
Investigators have also received a report of the man committing the same offence at a store in Federation Square on 22 May where he pocketed $155.
Investigators have released an image of a man who they believe may be able to assist with their enquiries.
Anyone who recognises the man is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au