Petrol prices in Wales are the lowest in the UK.
The RAC surveyed forecourts and found the average price of a litre of unleaded in Wales was 118.0p in April and in the month it had moved up just 1.09p.
Even diesel costs were towards the lower end of the price scale at 119.94 when the cheapest in Northern Ireland was 119.37p.
The RAC says lowered bunker prices and a rise in the value of the pound puts retailers in a position to cut prices even more as the highly competitive summer season approaches.
The motoring organisation suggests a 2p cut is realistic this month.
“The combination of a lower oil price and a 4% rise in the value of the pound has made it far cheaper for retailers to buy in their fuel. In the interest of transparency this saving should be passed on to motorists on the forecourt in the next few days,” said RAC fuel spokesman Simon Williams.
“We have seen one supermarket reduce their petrol price by half a pence a litre and a very slight reduction in the national average but there is far more to come if retailers are not to be accused of ‘rocket and feather’ pricing.