Motorists have questioned why petrol and diesel prices are not falling in line with the collapse in crude oil prices.
Some retailers have been accused of "opportunistic" profit-taking over their failure to cut prices at the pumps.
Crude prices are at their lowest in two years, down from $71 a barrel in October 2018 to close to $50 at the moment.
Prices of crude have fallen heavily this year as the coronavirus outbreak caused demand from China to drop sharply.
Carbon tax on motor fuels went up 2c a litre in the Budget, but consumer groups said there should be cuts passed on to drivers from the fall in crude costs.
Chairman of the Consumers' Association Michael Kilcoyne questioned why prices were not falling. He accused retailers and oil wholesalers of pushing up prices quickly when crude prices rise, but failing to cut prices when crude costs fall.
"We need the Competition and Consumer Protection Commission to look at this," he said.
But Conor Faughnan of AA Ireland said he expects prices to have fallen when his organisation issues its next petrol and diesel price survey in the coming days.
He said the situation was complicated by the fact that crude is priced in dollars, but when prices are converted into euro the fall in wholesale oil prices is sometimes not so dramatic.
Mr Faughnan said there was little evidence that pump prices go up immediately and fall slowly when crude prices drop. But he added: "There certainly are some retailers who are being opportunistic and are charging too much because they can get away with it."
AA Ireland said there was an onus on drivers to only choose petrol and diesel retailers that offer good value.
Applegreen had no comment. It is the largest petrol and diesel retailer in the State.
David Blevings of the Independent Petrol Retailers' Association said retailers only pass on increases and decreases in the wholesale price of fuels, which move daily. He said retailers have no control over wholesale prices.