The South Australia government agency fined six petrol stations nearly $20,000 for illegal pricing.
The watchdog ran checks and found issues mainly around fuel price guidelines.
Customers were asked to call in if they spotted price inflation at pumps during the audit.
No brand names or location details were released yet.
Total fines total after ongoing patrol visits.
In Greater Western Sydney, Blacktown motorists now spend extra for fuel than surrounding districts.
Regular pump checks reveal the area’s prices outpace other local stations.
The price disparity means drivers there spend more per litre each time they fill up.
The gap has widened than what regulators expect in usual regional swings.