Police are investigating two hold-ups overnight.
The first was at Roxby Downs at about 12.15am when a man armed with a tyre lever threatened staff at the Roxby Tavern bottle shop as they were closing.
He stole an amount of cash before running off.
The second robbery was at 1.36am when a hold-up alarm was activated at the United petrol station on Main North Road, Pooraka.
An offender armed with a knife grabbed the till and ran off.
He is described as being 5′ 8″ and wearing a long sleeved hooded jumper with a check or tartan pattern, a white t-shirt, black jeans and red shoes.