A man threatened staff at an Alexander Heights service station with an axe before he fled with cash overnight.
Police were called to the Gull petrol station on Mirrabooka Avenue where the man used a small axe as leverage as he demanded money about 12.10am.
He stole money and fled on foot.
The man is about 20 years old and about 185cm tall with olive skin, a stocky build and short brown hair.
He was wearing a light blue jacket, dark blue cargo pants and sneakers.
Those with information on the robbery are asked to call Crime Stoppers on 1800 333 000.