Police have released CCTV images as part of investigations into the armed robbery of a service station at Seven Hills last week.

About 2.35am on Thursday 1 August 2013, a male armed with a knife entered the premise on the Prospect Highway.

He threatened staff with the weapon and demanded money.

The male obtained a number of mobile phones, but no cash was accessed. He then fled through a window in the administration office.

Police were contacted and immediately attended the location establishing a crime scene, which was examined by the Forensic Armed Robbery Unit. A search of the area, was conducted, with the assistance of a police dog, however the male was not located.

Detectives from Blacktown Local Area Command are continuing investigations into the robbery and have released closed-circuit television images of a man who may be able to assist with inquires.

The man depicted in the footage is described as being of Caucasian appearance with a pale complexion, thin build, brown hair and wearing a dark coloured hooded jumper and dark coloured back pack