Police are appealing for information from the public following an alleged armed robbery in Sydney’s south west overnight.

About 9.15pm (Friday 13 January 2012) three people entered a business on Campbell Hill Road, Chester Hill and demanded cash from the store employee.

The female staff member, who was standing behind the service counter, showed the group the empty cash register.

One offender then approached her behind the counter and demanded cigarettes.

It is alleged one of the group was armed with a firearm and another armed with a machete.

The three then fled the store on foot with an amount of cash and cigarettes.

The female employee was not injured.

Police attended a short time later and established a crime scene which was examined by specialist officers.

Bankstown Detectives are investigating the incident and wish to speak to three people they believe may be able to assist with their inquiries.

The first person is described as male, 165-175cm tall, skinny build and wearing a black hooded jumper and pants.

A second male is described as 150-170cm tall, medium build, with a light-coloured hooded top, black jumper and dark pants.

Anyone who witnessed the incident or noticed suspicious activity in the area is urged to contact Bankstown Police or Crime Stoppers on 1800 333 000.