The offender entered the Anchorage Drive outlet with a towel draped over his head about 7.30pm on January 17. He demanded cash while wielding a screwdriver.
The man fled, with a small amount of money, in a waiting silver Holden Commodore VZ wagon.
The robber was described as aged between 25 and 35, about 185cm tall with fair skin and athletic build. He was wearing a sleeveless navy shirt and dark shorts. Call Crime Stoppers on 1800 333 000.