Canberra woman Jane Penders bought a four-acre property in Gunning in 2018 and struggles to understand how fuel can be consistently cheaper in a town that is home to less than 1000 people and just one petrol station.

At the same time drivers were being charged an average of 137.9¢ per litre for unleaded petrol in Gunning this week, according to the NSW government's Fuel Check website, price comparison website MotorMouth listed the average price across the ACT as 144.1¢ per litre.

Ms Penders and her partner Jay Dryden try and hold off on buying petrol in Canberra during the week so they can fill up on weekends, which they spend in Gunning.

"Gunning's got one service station, so they could charge pretty much whatever they want because people would have to pay it if they needed petrol, but they don't do that," Ms Penders said.

"[Blaming Canberra's high prices on the lack of competition] just sounds like a bad excuse.

"Canberra's not an easy town to get around without a car and if the ACT government really wanted to look after Canberrans, [a government-regulated petrol price monitoring scheme] would be one way to do it."

The ACT government is resisting calls from the National Roads and Motorists' Association to introduce a real-time price monitoring scheme like those in NSW and Queensland. Publishing real-time data online is designed to make it easier for drivers to find the best deals and encourage the more expensive retailers to drop their prices in order to stay competitive.

Another option would be a scheme modelled on Western Australia's FuelWatch, which requires service stations to notify prices the day before they come into effect and to set them in stone for 24 hours.

The territory government has instead encouraged drivers to use free, independent websites to look for the lowest prices.

Chief Minister Andrew Barr has repeatedly blamed the capital's high prices on a lack of competition, describing increased competition and Australian Competition and Consumer Commission intervention as the only solutions to drive prices down.

The commission referred the Sunday Canberra Times' enquiries to existing media releases and recent reports, which said factors that influence petrol prices in Canberra were more akin to those in regional areas than in Australia's five largest cities, which have price cycles.

Other than a lack of competition, the commission said factors that influence prices in Canberra include lower volumes of fuel being sold and lower convenience site sales than in the larger cities.

Australasian Convenience and Petroleum Marketers Association chief executive Mark McKenzie said a variety of factors influenced petrol retailers' pricing decisions.

He said while he would like to see more competition in Canberra's "mature market", service station sites didn't come onto the market often and only very aggressive new entrants like Costco at Majura Park and Metro Petroleum in Fyshwick tended to shake things up.

"The principal difference between Canberra and other capital cities like Sydney and Melbourne is the intensity of competition, which is driven by the size of the market and the presence of independents," Mr McKenzie said.

"With independents, their mechanism for competition is price discounting.

"Service stations are not a government service, they're run as a business and you either sell a lot of fuel at lower prices or less fuel at higher prices to cover your costs."

Mr McKenzie said research showed almost half of the people who went into a petrol station also bought something other than fuel.

While independents tended to sell cheaper petrol, he said they usually charged more for food and drinks than the big players.

Asked about the difference in prices between Canberra and small towns with no competition like Gunning, Mr McKenzie said retailers made pricing decisions based on their individual circumstances.

"Gunning's a little bit different because they're really trying to lure people off the Hume Highway, and the way to do that is to have cheap fuel," he said.

"That service station also has a captured market there so the volumes being sold mean it probably doesn't need to charge as much [as some petrol stations in Canberra]."

Mr McKenzie said the association was not against government-regulated price monitoring schemes, but he did not believe they drove prices down.

He said they simply made the market more visible.

But drivers like Ms Penders and Jana Prencel said action needed to be taken to stop Canberrans being ripped off.

Ms Prencel was born in the ACT and still works in the capital, but moved across the border to Karabar as a first-home buyer because it was more affordable.

She now only fills up in Queanbeyan, where she said she saved about $15 a tank on average.

"It's all well and good to check [petrol prices] on a free app or a website, but if it's not regulated, I just don't think it's good enough," Ms Prencel said.

"It's just way too expensive and why would I bother filling up in Canberra after work when I can get it much cheaper just over the border?"

Both women said they liked the idea of government-regulated petrol price monitoring.