He pushed a staff member out of the way, snatched the till from the counter and ran from the Prindiville Drive store about 11am on March 9.
Police later found the till empty of cash about 200m away near a major supermarket.
A witness believes they saw the offender get into a white Holden Commodore on Dellamarta Road with another two males in the car.
He was described as Caucasian, about 175cm tall with big eyes, a deep voice and square face.
Police believe the male pictured can help with their inquiries.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000.