The Australian Competition and Consumer Commission's quarterly probe into the petrol industry showed that while Australian petrol prices were at their lowest levels since 2002 last financial year, gross retail margins have soared.

ACCC chairman Rod Sims believed the full savings on crude oil and refined petrol prices were not being passed onto consumers.

"Canberra's probably enjoying the lowest fuel prices in 2015/16 than it has for a number of years, probably a decade, once you adjust for inflation but it should be having even lower prices, probably three to four cents lower because the margins in Canberra are quite high," Mr Sims said.

"The gross retail margins in Canberra are really higher than I think you can justify by cost or any other difference."

When issued with a 'please explain', Mr Sims said petrol retailers were coy.

"I think what's going on is the petrol companies see the prices are low, perhaps think people will be satisfied with that and have taken the opportunity to improve their profits. We've asked them for an explanation and not had very good answers and I suspect they've seen it as an opportunity for a bit of profit recovery," Mr Sims said.

The average fuel price in Canberra for the June quarter was 127.9 cents, up from 116.4 cents the previous quarter.

In the same period, Sydney recorded an average of 125 cents per litre, Melbourne 125.1 cents, Brisbane 127.7, Adelaide 116.9 and Perth 123.4.

Mr Sims said Canberrans should shop around and even consider heading over the border in search of better prices.

Service stations in NSW are now required by law to notify the government and customers when they change their prices via the NSW Fuel Check website, which Mr Sims said could open up a price divide between Canberra and Queanbeyan.

"In the most recent quarter Canberra prices were about a cent higher than Queanbeyan prices, you'd have to wonder why that's so but nevertheless it's only one cent," Mr Sims said.

"It'll be interesting to see what happens to that differential once the NSW Fuel Check [website] goes ahead because if that allows people to shop around and people do reward the discounters and Queanbeyan prices go below Canberra prices then there maybe a lesson there in getting more information out to the public."

However Commsec economist Savanth Sebastian said while cheap global oil has helped to alleviate pain at the pump for the past few weeks, an upcoming meeting of oil producing nations has skittled prices.

"Unfortunately it is very likely that the lows for petrol have been reached for a while," Mr Sebastian said.

Leading up to that meeting it is likely that oil prices will remain volatile on speculation that oil producers may look at avenues to limit output and thus support prices.

"Importantly motorists should continue to keep an eye on the discounting cycle, because at the low point in the cycle motorists should still be able to pick up petrol at or below the cost price."

There are plenty of different apps and websites you can use to find the best deal on fuel, including Motormouth, PetrolSpy, or the NRMA's Bowser Buster.

Mr Sims said Canberrans needed to use their purchasing power to put pressure on local retailers to keep their prices competitive.

"All we can do is urge Canberra motorists to shop around. I know that sounds trite but it's really important that people reward the discounters," Mr Sims said.