Petrol prices in Northern Ireland have increased by 6.4p in the last year - one of the biggest price hikes in the UK.
The average cost of petrol is running at 123.8p per litre, new figures show.
And owners of diesel cars are also bearing the brunt of increases, with the average price per litre rising by 6.9p year-on-year to 125.7p.
The past week alone has seen significant change in prices, with both petrol and diesel increasing by 1p.
It means drivers of a medium-sized car could be paying out £71 to fill their tanks with petrol - £4 more per tank than 12 months ago, when prices were at 117.4p.
And it is a similar picture for diesel cars. It now costs £72 to fill up a medium-sized car - also £4 more expensive than May 2017 when diesel was 118.8p.
The figures emerged after an analysis by fuel price index by Confused.com.
Dr Catriona MacArthur from the Consumer Council said rising fuel prices were a growing concern.
"Today's figures from Confused.com, which show an increase in petrol prices, will come as an added burden to Northern Ireland consumers," she told the Belfast Telegraph.
"Our research confirms that rising prices are the number one concern for Northern Ireland consumers.
"We are encouraging consumers to look at ways to cut their household bills, and we have a range of resources to help."
The average price of petrol in the UK is now 124.4p - up 0.9p up week-on-week.
And diesel has also increased by 1.0p to 127.5p, on average.