People are being urged to make sure all the alcohol is out of their system before they drive today.
Almost 1,000 people were arrested on suspicion of drink driving over the Christmas period last year.
Gardaí say 11% of fatal road crashes involving drink happen the morning after a night out.
Liz O'Donnell from the Road Safety Authority says be careful if you were out last night.
"Our Christmas message is very much now is to make people aware that even though they might do the right thing the night before, many people are inadvertently being breathalysed and breaking the law the following day," said Ms O'Donnell.
"11% of all the fatal crashed that happened this year - where alcohol was involved - actually happened between 7am and 11am."
On Christmas Day this year, 10 people were arrested on suspicion of drink-driving.
That is according to figures released by An Garda Síochána who also confirmed that a further 12 people were arrested between midnight and 9am on St Stephen's Day.
A number of the drivers stopped refused to give a breath sample when asked by Gardaí and will now automatically face a four-year driving ban.
