Canberra drivers are at the whim of oil companies, according to motoring groups, as the capital's petrol prices again remained steady and above national averages for the eighth week in a row, despite price fluctuations in other parts of the country.

Motorists in the ACT again paid an average of 157.9¢ per litre for unleaded fuel over the week leading up to Sunday. There has been only a 0.1¢ increase in the past eight weeks in Canberra.

The national average price dropped 3.3¢ to 150¢ per litre, after a rise of 4.1¢ in the previous week and despite predictions last week by analysts at CommSec that the price would rise again.

ACT Chief Minister Katy Gallagher said she had written to and met with the Australian Competition and Consumer Commission multiple times over petrol prices in Canberra but had failed to find a solution to the perpetually high price.

''Their advice back to me was they don't think there's anything about Canberra specifically that makes us pay more - other than there's probably an element of an affluent community there, the volume of sales, the fact that there isn't huge volumes sold here in Canberra and competition were certainly factors,'' she said.

''They're [the ACCC] certainly watching and are aware of the prices in Canberra.''

Colin Long, of the Motor Traders Association's service stations branch, said Canberra missed out on discounting cycles due to a lack of competition, particularly from independent operators.

NRMA's ACT corporate affairs manager, Ron Collins, accused oil companies of profiteering and said it was ''unfair'' Canberra was ''forgotten'' when it came to competitive discount cycles.

''We don't have price cycles here in Canberra, we don't have competition and there's no transparency as to how the fuel companies price their petrol here,'' he said.

Of the capital cities, Canberra was the third-most expensive behind Darwin and Hobart and was also more than 3¢ above the regional average.