Drivers are likely to face a second hike in toll rates in six months.
Tolls on some of the country's main roads, including the M50 and M1, are going up on Saturday.
Transport Infrastructure Ireland says it's "highly likely" the rates will rise again next January because of inflation.
It says an increase in the consumer price index of more than 3% will mean a guaranteed increase in tolls in January.
From July 1st, tolls on the M50 will go up by 30 cent for cars without tags to €3.50, while cars with tags will see a 20 cent increase, and on the M1, M7, M8, N6, N25 and N18, tolls for cars will rise from €2 to €2.10.