Police are treating robberies from two service stations in the Hunter Valley and an attempted robbery from a third as connected.
The first service station at Weston was targeted around 4.30pm on Tuesday when a man entered the shop on Cessnock Road and spoke to the operator, demanding cigarettes.
He was given a packet of cigarettes before driving off in a vehicle.
The same sequence of events took place in a separate service station robbery along Cessnock Road at Neath three hours later, and this time saw a man make off with an amount of cash.
A third incident occurred around 8.30pm at another service station on Wollombi Road at Cessnock but the would-be thief fled empty handed when the attendant phoned police.
Officers from Hunter Police District attended and have launched an investigation.
Detectives are working with several lines of inquiry including the theory that all three incidents were carried out by the same person.
Anyone with information is urged to contact Crime Stoppers.