The price of petrol and diesel at Irish pumps is set to rise 3-4c per litre from as early as this weekend, the head of forecourt chain Applegreen has warned.
World oil prices shot up this week after a drone attack on Saudi Arabia's biggest refinery site.
The effect on prices will be swift and likely to be sustained for some time, Applegreen's chief executive Bob Etchingham said.
The weakness of sterling was already putting pressure on the cost of oil - traded internationally in dollars, he said. "You will start to see increases at the pump from this weekend onwards," he said.
On Monday, the price of Brent crude oil posted its biggest one-day gain since the 1990-1991 Gulf crisis after the Saudi drone strikes caused the single worst disruption to supply ever.
The attacks highlight the vulnerability of the world's most important exporter and are expected to see oil prices remain elevated.
AA Ireland has warned diesel and petrol prices for drivers could rise by between 6c and 8c per litre, if the high crude prices are sustained.
Applegreen stunned the markets with the strength of its financial results yesterday - enough to send shares surging almost 10pc to €5.68 each.
The Irish company now operates here, in the UK and across four different markets in the US.
Its stellar first half financial results were marred however in its home Irish market.
Applegreen's chief operating officer Joe Barrett said management were shocked on Thursday when footage emerged on social media of a rat emerging from a sliced pan wrapper at a Dublin outlet.
Revenue across the group increased by 73pc to €1.48bn in the first half of 2019 versus the same period a year earlier. Gross profits in the period were up 145pc to €268m.