Diesel prices have overtaken petrol for the second time in months.
The national average diesel price at Gull is three cents more than 91 petrol. Gull's general manager Dave Bodger told AM the climbing prices of diesel are "unprecedented".
"I've unfortunately spent over 30 years in the industry and never before has diesel been more expensive than petrol," he said.
"It's tough for those of the public who run on diesel for their vehicles."
And while diesel prices climb, Bodger says 91 is mostly back to where it was before Russia's invasion of Ukraine.
"Petrol is back to where it was pre-Putin and pre-the Ukraine crisis, so diesel has remained high."
Bodger told AM diesel prices could climb further as Europe approaches its winter months.
"I hate predicting the future, but over time there's always a greater demand for diesel in the Northern winter," he said.
"Russia used to export a lot of diesel into Europe and there's a reduction in gas that's going to Europe, diesel is a substitute for gas, not a good one, but it generates electricity, it helps [the] industry grow. So diesel from around the world is flowing into Europe to replace the diesel they need."
Bodger says diesel is used to heat homes in the European winter and warns prices could get "worse".
But Bodger told AM the European winter isn't the only threat - the return of international tourism could play a part too.
"There'll be some form of competition between jet fuel, so there will be more jet fuel demand, jet fuel is a first cousin of diesel. So in the refining process, potentially jet fuel being required more, also pushes up the prices for diesel."
Watch the full interview above.