Motorists will face a fine of up to €1,000 from next month if caught texting on their mobile phones while driving.
Minister for Transport Leo Varadkar has signed a new amendment to existing legislation, which will come into effect on 1 May.
Anyone caught texting or accessing information on mobile phones will be given a mandatory courts summons and a fine.
Texting while driving is already illegal but there was a grey area surrounding the use of hands-free devices.
A spokesperson for the minister said he wanted to close a loophole that meant a driver caught texting on a phone resting in a cradle could potentially take a challenge.
The new legislation means a convicted driver faces a maximum fine of €1,000 for a first offence and a fine of up to €2,000 for a second offence.
If caught three times within a 12 month period, motorists will face a fine of up to €2,000 and a possible jail term of up to three months.
A Department of Transport spokesperson said texting while driving is considered so serious that no penalty points will be immediately applied when caught and instead the driver will be sent to court.
The Road Safety Authority has welcomed the tightening up of legislation for drivers caught texting on their mobile phones.
Brian Farrell said "distracted driving" is probably a contributory factor in 20% to 30% of all collisions that happen on the State's roads.