The government's decision not to ban all smacking of children will be opposed, the Northern Ireland Children's Commissioner has said.
Commissioner Nigel Williams is carrying out reseach
Nigel Williams and the other three UK commissioners claim that children's human rights are being breached.
The law on smacking children is being tightened but parents will be allowed to carry out "reasonable chastisement".
Mr Williams said children were the only people in the UK who could be hit without consequence.
He said his office was researching how often children are beaten and what other methods of discipline parents could use instead.
The commissioner said children were hurt physically and emotionally when they were hit by their parents.
All four UK children's commissioners have called on the government to ban physical punishment altogether.
They said protecting it in law confused parents and inhibited child protection.
The commissioners said research showed that children were upset by smacking and adult approval of it.
In a letter to Education Secretary Ruth Kelly, the commissioners said the rules should be changed as a matter of "fundamental principle".
Current legislation allows parents to hit their child mildly as a "reasonable punishment".
Prime Minister Tony Blair has admitted smacking his older children. Other campaigners say smacking should not be confused with child abuse.