Police are investigating following the armed robbery of a service station near Mackay overnight.

Preliminary investigations indicate at around midnight a man entered the business on the Bruce Highway at Coningsby and approached the counter armed with a knife.

The man demanded money from a female staff member, before fleeing the with a sum of cash.

He left the scene with another unknown person who was waiting outside the business.

No one was physically injured during the robbery.

The man is described as Caucasian, aged in his early 20’s with a slim build, around 170- 180cm tall and was wearing a balaclava, a black long sleeved shirt, black shorts and no shoes.

The second person was also wearing a black long sleeved shirt and shorts and no shoes.