The average price gap between Canberra and the five largest Australian cities has also ballooned from 5.5 cents in July to 17 cents a litre in January.

In 2013-14 the average difference for Canberra was 6.8 cents a litre.

The results were published in the first quarterly report under new petrol monitoring arrangements the Abbott government announced in December.

The report confirmed lower oil prices failed to turn around the capital's age old fuel problem.

"The decrease in international refined petrol prices did not flow through to retail petrol prices in many regional locations to the same extent as it did in the five largest cities," the report said.

Prices in Canberra fell by 31.1 cents from July to January from 157.3 cents a litre to 126.2 cents, while in the same period Sydney prices fell by 45.6 cents from 150.2 to 104.6 cents.

The average fall across the country's five largest cities in the same period was 42.6.

Prices are now on the rise again across the country.

The national average Australian petrol price rose by 0.3 cents per litre last week to 119.8 cents a litre, according to the Australian Institute of Petroleum.

"At the beginning of February 2015 retail petrol prices in the five largest cities started to increase, following a rebound in international petrol prices," the ACCC said.

The good news is, over the past week, Sydney and Canberra were on the same page - Canberra at 117.6, while Sydney was at 117.3 cents a litre.

This trend is expected to continue.

"The differential between average prices across all regional locations and the five largest cities is expected to narrow in the remainder of the March quarter 2015," the commission said.

The report confirmed out of the major cities Darwin residents still pay the most - staying higher than Hobart and Canberra.