Motorists can expect to see a drop in petrol and diesel prices of between 8c to 10c per litre over the next three weeks.
AA Ireland said the price of Brent crude oil, which dictates European fuel prices, has fallen from an average of $106 during March to $90 today.
The organisation said there is a three- to four-week lag between a change in prices and a change at the pumps.
AA Ireland's Director of Policy Conor Faughnan says a number of studies by the organisation showed fuel retailers on average faithfully followed the drop in oil prices, despite a perception by consumers this was not the case.
Almost 60% of the cost of fuel goes in tax and prices are also affected by the fact that fuel is bought in dollars.
The eurozone crisis has made the euro weaker against the dollar this year, which has had the effect of making petrol and diesel more costly.
Mr Faughnan said 55c of the cost per litre reflected the price of crude oil.
The AA's price watch survey, which is conducted in the first week of every month, showed petrol prices have fallen from 165.9c in May to 162.9c in June.
It showed diesel has dropped from 157.5c to 153.6c over the same period.