Petrol prices have risen for the fourth consecutive month and the average cost of unleaded is now 117.3 cent per litre, according to the Automobile Association.
A 15 per cent increase in petrol prices since February has added more than €260 a year to the fuel bill for an ordinary family car, the AA estimates. Diesel prices have been more stable and are almost unchanged, at 108.4 cent, compared to last month.
AA public affairs manager Conor Faughnan said that the continuous increase in fuel prices was a significant contributor to Ireland's inflation rate.
"Diesel prices did not rise as much, which may seem strange, but is in fact a normal pattern for this time of year. The demand for gasoline is higher in the Northern Hemisphere summer, especially in the US, and this year is no exception."
The AA calculates that an ordinary family car typically uses 150 litres of fuel in a month. The price rises since February, when the average cost of petrol was 102.6 cent, means that the cost of a month's fuel rose from €153.90 in February to €175.95 in June.
In spite of recent increases, petrol prices in Ireland remain relatively low by international standards. In April, unleaded cost an average 137 cent in Northern Ireland, 138 in Britain, 127 in France and 132 in Germany.
There are also large differences between the cheapest and most expensive prices, with some Galway garages selling for just over 110 cent and the dearest in Dublin, Statoil on Usher's Quay, charging 159.9 cent.