Canberra petrol stations are ripping-off customers according to both the ACT Government and the Opposition, but exactly how to bring prices down is up for debate.

Key points: The Canberra Liberals plan to introduce a real-time petrol price watch scheme if elected

The Canberra Liberals plan to introduce a real-time petrol price watch scheme if elected Data shows ACT petrol prices are consistently higher than in nearby locations

Data shows ACT petrol prices are consistently higher than in nearby locations Chief Minister Andrew Barr has asked the ACCC to investigate Canberra petrol retailers

The Canberra Liberals have pledged to introduce real-time petrol pricing if they are elected in 2020, in a bid to bring service stations in the ACT into line with other areas like Queanbeyan and Bowral.

Opposition leader Alistair Coe said on Tuesday that it was unfair Canberrans were paying 20-30 cents more per litre than others in comparable locations.

"That may mean Canberrans are paying about $20 more than the rest of the country to fill up the tank. We need to make petrol more affordable for all Canberrans," Mr Coe said.

According to Liberal party figures, the average price for unleaded petrol in Canberra is about 145.9 cents per litre compared to 125.2 cents per litre in New South Wales.

"I think the Canberra community is absolutely fed up with the petrol prices that we're forced to pay," Mr Coe said.

"It simply doesn't stack up that prices in Canberra should be 30 cents more per litre than places just up the highway.

"What is clear is that the Government's do-nothing approach is failing."

Can real-time pricing reverse a market failure?

Under the Liberal party's proposed scheme, petrol retailers would be required to report changes to fuel prices by 6:00am every day, and those prices would be fixed for 24 hours.

Opposition leader Alistair Coe said consistently high fuel prices indicated possible "collusion" between retailers. ( ABC News: Mark Moore )

But Chief Minister Andrew Barr said real-time pricing data was already available through Petrol Spy, directing buyers to the cheaper outlets in places such as Pialligo, Fyshwick and Canberra Airport.

"Canberrans are being gouged elsewhere and this is clearly a market failure," Mr Barr said.

"It's why I wrote to the ACCC some time ago, I went up to Sydney and met with the Commissioner and have asked for the ACCC to do one of their deep-dives into this petrol market."

Mr Barr said he was sceptical of the Liberals' plan for fixed prices over a 24-hour period.

"You want to be careful in designing something like that, that you would allow people or retailers to lower their price — you don't want them fixed at a higher price and not be able to change it for 24 hours," he said.

"The advice from the ACCC is that these schemes don't necessarily lower prices."

Mr Barr claimed there were not enough independent retailers in the ACT market to drive prices down.

And he said there was no excuse for big businesses who kept their prices high.

"It is possible to sell fuel at that low a price and stay in business in Canberra," he said.

But Mr Coe said more need to be done to investigate why Canberrans were being gouged at the bowser and accused the ACT Government of failing to take action on the matter.

"It's all very well for Mr Barr to say we need more independents, but there are certainly a lot of players in this market," he said.

"He is, in effect, saying that there is some collusion taking place in this market."

The ACCC was approached for comment.