Police are investigating a service station robbery at Burton overnight. 

At 2.40am, a man approached the night window of the Caltex service station on Waterloo Corner Road and demanded money from the console operator. 

It is not known if he was armed with a weapon. 

He left on foot with a small amount of cash and although a police dog tracked him for a short distance, the offender was not located. 

He wore a black hooded top, blue jeans, sneakers and black framed mirror glasses. 

He is described as Caucasian about 25 years and with ginger or red facial hair. 

If anyone saw the robbery or the man leaving the area, they are asked to call BankSA Crime Stoppers on 1800 333 000 or report online at www.sa.crimestoppers.com.au  

Since Friday, this is the seventh robbery on a business premise across the metropolitan area.  

Fortunately there were no injuries in any of the robberies, but staff are often left traumatised over the incidents. 

The penalty for an aggravated robbery (robbery with a weapon) is life imprisonment and police will be examining security vision and collecting evidence in all incidents in a determined effort to arrest the suspects.