There's fresh misery for motorists as further road toll increases are on the way next year.

The Business Post reports Transport Infrastructure Ireland has warned that a failure to hike prices will scare off investors in other projects.

It's expected to increase charges by up to 20 cent per trip as it prepares to launch MetroLink.

The government delayed previous road toll increases of between 10 and 20 cent for six months earlier this year, following to a public backlash.