The assembly voted in favour of a smacking ban in 2004

A legal expert has claimed the assembly government could start the process to make smacking a criminal offence.

Some children's charities have welcomed the prospect, saying a ban would clarify a confusing issue for parents.

But Family and Youth Concern said it was wrong to pass laws on how parents should bring up children.

Norman Wells, from Family and Youth Concern, which researches the effects of family breakdown, said: "Nobody has got a right to come along and tell you to eat up your greens, or tell you what time to go to bed.

If there were a ban on smacking, it would very clearly say that violence - all violence - against children is unacceptable Lynne Hill, Children in Wales

"But you do have that sort of right and power with a child who is your responsibility.

"Parents stand in a unique relationship to their children, and along with that unique relationship and that unique responsibility, comes unique authority," he added.

Lynne Hill from the charity Children in Wales said it would be disappointed if a proposal from the assembly government was blocked at Westminster.

She said: "If there were a ban on smacking, it would very clearly say that violence - all violence - against children is unacceptable.

"I think the issue at the moment is that parents are unclear where they stand in terms of they want to work towards positive parenting, towards non-violent parenting, but the law doesn't give them that clear line."

If you're asking if I personally would like the assembly to have this competence, then the answer certainly is yes Welsh Assembly Government Deputy Health Minister Gwenda Thomas

On Thursday, Kevin Brennan, the MP for Cardiff West and the children's minister in the UK Government, said there were no plans to change the existing laws on child smacking.

Under the 2004 Children's Act, which came into force in January 2005 mild smacking is allowed but any punishment which causes visible bruising, grazes, scratches, minor swellings or cuts can result in action.

Former government legal adviser Professor David Lambert said a request for the right to legislate - known as a Legislative Competence Order (LCO) - proposed by the assembly government on vulnerable children - was so broad it could be an enabling power for the assembly to ban smacking.

Legal position

"The only way to challenge it then would be through the courts," he added.

The Labour-Plaid coalition government made it clear that, if it had the right to legislate, it would use it to ban smacking.

The Wales Office said discussions were underway in the assembly government on the vulnerable children LCO, but said it had not been submitted yet.

Deputy Health Minister Gwenda Thomas told a committee of AMs that she was in favour of Wales having its own law.

She said: "I am unable to confirm the legal position, but I will undertake to write to the committee to provide clarity as soon as I'm able.

"If you're asking if I personally would like the assembly to have this competence, then the answer certainly is yes."