The price of petrol and diesel is set to rise again from midnight tonight.
Government excise duties, which were cut as part of measures to combat the cost-of-living crisis, will be reinstated on a phased basis.
Petrol will increase by 6 cent a litre and diesel by 5 cent from Thursday.
The Consumers Association of Ireland said the move will have both a direct and knock-on effect on consumers, making transport and goods more expensive.
"If this fuel is being used for carrying product to the supermarket, then the only one who can pay for it is the consumer," the group's chairperson Michael Kilcoyne said.
"And the consumer is going to have their goods increase (in price) so whoever is transporting it can cover the costs. It means there will be further inflation as a result of this," he told Newstalk radio.
Mr Kilcoyne added it is poor practice to increase costs for consumers "at a time when Government talks about the amount of revenue they have".
"I would call on [the Government] to defer this to at least the end of the year.
"Six cents on a litre of petrol, five cents on a litre of diesel is a lot of money, because in country areas there is no public transport, they have to have a car," he added.
