RACV manager vehicle engineering Michael Case said a drop in the retail price of unleaded petrol in regional Victoria to reflect falling world oil prices should have happened sooner. 

Bendigo motorists have been paying higher fuel prices than motorists in places such as Geelong, Melbourne and Sydney in recent days. 

While fuel was sitting at 126.3 cents a litre at one Bendigo outlet on Tuesday, prices in Melbourne varied between 112.7 cents and 114.9 cents a litre.

Mr Case said a service station in Bendigo charging 126.3 cents a litre would be "reasonable given current circumstances" but that further drops across the board were needed.

"You'd be hoping others would be on their way down... to really be providing fuel at right price relative to current prices in Melbourne and Geelong," he said.

Mr Case said fuel prices should have been getting lower and lower over the past three months due to the fall in world oil prices. 

He said Melbourne had not experienced unleaded fuel prices of 114 cents a litre for at least four years. 

"There's been a progressive reduction in retail fuel prices for last almost three months, (but) we've seen a slower decrease in retail prices in regional areas," he said.

Mr Case said price drops had also been quite variable between regional centres.

''Our major concern is that regional centres have not been following the price down quickly enough," he said.

Mr Case said significant variances between nearby regional centres which could not be related to transport or supply costs were also concerning.

"There are some variances between nearby regional centres which relate to differences in local competition," he said.

"It's our view prices should have come down more quickly to a level closer in price to Melbourne."

He said additional factors were at play in Geelong, Sydney and Adelaide where Coles had capped the price of unleaded petrol between December 22 and January 4.

"I do not recall ever seeing a (fuel) company doing this before," he said.

"It is good news for motorists in the sense they can be certain of fuel prices over this period."

Mr Case said he did not know why Coles had chosen the three specific sites to cap prices.

He said Melbourne prices hovering between between 112.7 and 114.9 were a reflection of Geelong's capped prices.

"It's very close to the price capped in Geelong, it says Melbourne prices are following Geelong," he said.

He said Coles was not expected to change their prices until next Sunday, ensuring prices would remain at the lower end of the fuel cycle, where they had been falling to for about 12 weeks.

"It's the most unusual circumstances, but great news for motorists," he said.