Police have released CCTV as they appeal for information after a South Sydney service station was robbed by a man armed with an uncapped syringe last week.

Just after midnight last Monday (11 January 2016), a man entered a service station at Tempe, took a bottle of water and left without paying.

About 1.30am, the man returned to the service station armed with an uncapped syringe and threatened the console operator, demanding cash.

The 23-year-old male console operator handed over cash before the armed man ran from the store.

No one was injured.

Police from Newtown Local Area Command attended and established a crime scene, which was examined by specialist forensic officers.

Detectives have released CCTV vision of a man who they believe will be able to assist with their inquiries.

He is depicted as being of Caucasian appearance, aged in his late 30s, with a medium build, black hair, a goatee and stubble on his cheeks, and a distinct mole on his right cheek.

He is wearing a grey and brown baseball cap, a black t-shirt, three-quarter denim jeans, and was barefoot.