At about 1.40am, a man armed with a crowbar and a knife entered the BP service station on Sir Donald Bradman Drive and demanded cash.
He fled with an amount of money and was last seen running behind the service station, possibly to a car.
No one was injured.
The suspect is described as being of Caucasian appearance, about 180cm tall, slim build, and was wearing a black balaclava, black jacket and black shorts.