Police are appealing for public assistance and warning small business owners to be vigilant following a spate of armed robberies in inner-Sydney recently.

Since May 2012, officers from Newtown Local Area Command have been investigating the armed robberies of five small businesses in the region.

Convenience stores and fast food outlets in Camperdown, Newtown and Erskineville have been targeted and detectives believe all the robberies are linked.

In each incident a man has threatened store employees with a screwdriver while demanding money.

In the most recent incident, about 8.45am yesterday (Saturday 16 June 2012), a man walked into a bottle shop on Parramatta Road, Camperdown, and threatened an employee with a screwdriver.

He demanded money from the register before fleeing with a sum of cash.

Detectives from Leichhardt Local Area Command are investigating this incident, which is also believed to be linked.

The man is described as being of Caucasian appearance, about 157cm tall, aged 30 to 50 years, and of thin build.