Detectives are investigating the armed robbery of a supermarket in which an employee was assaulted at Acacia Ridge this afternoon.

Around 3pm a man entered the business on Mortimer Road before threatening the store attendant with a knife and demanding he hand over cash from the till.

The man then punched the 43-year-old employee in the face before stealing a sum of cash from the register and fleeing the scene.

The staff member sustained minor facial injuries.

The man is described as being Pacific Islander in appearance, aged in his 20s and wearing a face mask, red hoodie, dark blue track pants and gloves.

Investigations are continuing.