Police are investigating following the armed robbery of a delivery driver in Sydney’s west yesterday.

About 9.15pm (Wednesday 8 June 2016), an 18-year-old man attended a home in Alpine Place, Horningsea Park with a delivery.

As he returned to his car, he was approached by a man who produced a knife and demanded cash.

The 18-year-old was chased by the man before he dropped his change bag.

The man took the change bag and was last seen running down Alpine Place.

Officers from Green Valley Local Area Command were notified of the incident and established a crime scene.

Police investigating the incident would now like to speak with a man who may be able to assist with inquiries.

He is described as being about 20-years-old and of Caucasian appearance and 170cm tall.

He was last seen wearing a white hooded jumper and black tracksuit pants.