Police are appealing for public assistance following an armed robbery at a service station in the Shoalhaven this morning.

About 7.30am (Monday 17 October 2016), a man armed with a knife entered a service station on the Princes Highway at Tomerong, south of Nowra, and threatened the attendant.

The man escaped with a sum of cash, running from the store and entering a white Mitsubishi sedan, thought to be a 2000-2006 model, which was driven north on the Princes Highway.

Police arrived a short time later and established a crime scene.

They are now seeking assistance from any person with information about the incident, including anyone who was driving along the Princes Highway at Tomerong about 7.30am and has a dash-cam in their vehicle.

Detectives are also seeking to identify the man who is described as being of Aboriginal/Torres Strait Islander appearance and aged in his 20s or 30s.

He was wearing a black hooded jumper, dark wrap-around sunglasses, light-coloured shorts and dark-coloured casual shoes.