Police are investigating the armed robbery of a petrol station at Lansvale in Sydney’s south west early this morning.

About 12:15am today (Thursday 19 April 2012), police were called to the petrol station on the Hume Highway near Lansdowne Road following reports of a robbery.

Investigators have been told a man, who had his face covered and was armed with a firearm threatened an employee at the service station.

He was handed cash and cigarettes and fled the petrol station on foot and was last seen running north along the highway.

Officers from Cabramatta Local Area Command and the Dog Unit attended the petrol station and conducted a search of the area but were unable to locate the man.

Detectives are now investigating the armed robbery and are looking for a man who has been described as being about 180cm tall, with a solid build and wearing a dark grey beanie, dark grey hooded top and tracksuit pants and white shoes.