Slapping children is linked to poor outcomes for them in later life including suicide attempts, heavy drinking and drug use.
Writing in the Irish Medical Journal, Professor Alf Nicholson from Temple Street Children's Hospital said parents are still physically punishing their children despite the introduction of a ban in 2015.
He said slapping children can cause negative outcomes, even if the child is under 18 months.
Studies show that slapping is linked to increased aggression and anti-social behaviour.
Psychotherapist Joanna Fortune agreed, saying: "It's timely that we reignite this discussion and look at positive alternatives for more creative and helpful forms of discipline for children.
"Because, for me, discipline should always aim to teach the behaviour you want to see from your children rather than punish behaviour you don't want to see."