Drivers of petrol cars feel pinch far more than diesel
Drivers of petrol cars have suffered a 13pc hike in their fuel bills in the last six months - and prices are continuing to rise.
But motorists who choose diesel engines are paying substantially less. The AA says that prices are up just 8pc in the same period.
A survey by the Irish Independent reveals the wide disparity of prices charged at garage forecourts.
In some cases, there is a 10c-per-litre difference.
In our survey of 32 garages, the cheapest petrol was at the Applegreen service station on the M1 at Balbriggan, Co Dublin, at 138.8c per litre.
This is 7.1c cheaper per litre than the dearest, Texaco on the M7 Mayfield Service areas, near Monasterevin in Co Kildare.
It also shows:
The cheapest place to buy diesel is Maxol in Harold's Cross in Dublin, where it costs 121.7c.
This is 10.1c cheaper per litre than the most expensive, Topaz at the M8 Cashel service area in Tipperary.
The AA says the average price per litre of petrol now stands at 145.3c. This is up 16.9c since February - a rise of more than 13pc.
Diesel costs on average 132.3c per litre, compared with 122.4c in February. This is a rise of just over 8pc.
And the survey also shows that Applegreen, which operates service areas across the motorway network, charges different prices in some stations.
The cost of a litre of petrol at Applegreen on the M1 south service area in Balbriggan is 138.8c, but less than 30 minutes along the motorway at the M1 north service area in Castlebellingham, it is 4c more expensive.
This also applies for diesel, which has a 2c price difference between the two stations. Applegreen could not be reached for comment.
Fuel prices are based on a number of different factors, including global oil prices, which have fallen in recent years.
But AA spokesman Conor Faughnan said prices were also seasonal.
"They (petrol and diesel) both derive from crude oil, so you'd think they would both equally change in price, but the price comes down to a seasonal factor," he said.
Diesel is more in demand in winter, as it is used for home heating.
"Diesel becomes more expensive in winter in the northern hemisphere because of this, whereas petrol tends not to be affected," he added.
Less tax is imposed on diesel, which also affects the year-round price. However, in summer the price gap widens as petrol is more in demand.
In July 2015, the gap between petrol and diesel was 13c per litre, nearly a 6c difference compared to January of this year.
Mr Faughnan said the rise in demand for petrol was down to use in other countries.
"A lot more leisure miles are travelled in the US in summer, which leads to a greater demand for petrol. That's a fact of the market," he added.
Dermott Jewell of the Consumers' Association of Ireland said it was "hard to call" whether the price of petrol would rise or fall in the coming months.
It would largely be determined by the October Budget, he added.
"The Government takes a significant amount of money already. Many call for it to be reduced and it will be interesting to watch in the forthcoming Budget. It would be nice to see a reduced level of state intake," he said.
The current rate of duty on petrol in Ireland is 59c per litre.
The best advice to consumers was to shop around, he added.