Petrol prices increased by one cent to €1.81 per litre, while diesel rates remained steady at €1.74 per litre in August, according to the latest AA Ireland fuel survey.
Fuel prices were expected to rise following the reinstatement of the full excise duty on motor fuels on August 1.
However, a fall in crude oil prices benefited customers as it counteracted the excise duty rise. Crude oil prices fell just below $80 (€72) per barrel this month.
This relief, however, is unlikely to last longer as planned tax rises later this year will see the country having the highest tax on diesel in the EU.
Petrol taxes are also set to be among the highest in the EU when the scheduled carbon tax hike comes into effect on Budget night in October, the Irish Independent reported.
Separately, AA Ireland said electric vehicle owners can expect to pay an average of €916 a year to cover the national average of 17,000km per year, an increase of €39 per year month on month.