The South Australia regional watchdog fined six petrol stations nearly $20,000 for pricing violations.
The inspectorate ran checks and found faults mainly around fuel price guidelines.
Customers were urged to call in if they spotted overcharging at pumps during the audit.
No brand names or addresses were released yet.
Total fines accumulate after ongoing patrol visits.
In Greater Western Sydney, Blacktown motorists now face higher for fuel than adjacent areas.
Regular pump checks reveal the area’s prices sit above other nearby spots.
The gap means drivers there spend more per litre each time they fill up.
The gap has grown bigger than what regulators anticipate in typical regional swings.