The minister responsible for children in Wales has ruled out legislation to ban smacking during this assembly term.
Gwenda Thomas said the Welsh government was committed to stopping the physical punishment of children, but legislation should not be undertaken lightly.
Assembly members voted in favour of a call to change the law to stop parents smacking their children.
Wales' children's commissioner joined the call for legislation, saying the law should not condone smacking.
Mrs Thomas told AMs in the Senedd chamber that a large amount of preparatory work would be needed to change the law and ruled out any legislation in this assembly term, which ends in 2016.
But she said she was "committed to retaining the option to legislate at a future date if we can't achieve the significant change we seek through other means".
"I would be fearful of criminalising parents, especially our most vulnerable," she said.
A cross-party group of four AMs wanted the Welsh government to introduce legislation to outlaw smacking by removing the defence of "chastisement" for assaulting a child.
The intention was to remove the legal defence of "reasonable chastisement" or "reasonable punishment".
The motion - passed by 24 votes to 15 - is not binding on the government.
Members of all parties were allowed free votes, with ministers abstaining.
One of the AMs proposing the motion, Labour's Julie Morgan, said she wanted the law to give children the same protection as adults.
"That is our priority, the goal isn't to criminalise parents," she said.
But her Conservative opponent Darren Millar said: "I firmly believe parents should have the right to chastise their children.
"I think there should be less interference in family life, not more."
Wales's children's commissioner has joined the call for a change in the law to stop parents smacking their children.
Children's Commissioner Keith Towler said physically punishing children does not work and there was "no such thing as a safe smack".
Mr Towler, who is appointed as an advocate to speak up for young people on issues concerning them, said: "Children should be entitled to the same level of protection as adults. There's no such thing as a safe smack."
He added: "A change in legislation will help shift attitudes and behaviour relating to assaulting children - something which can't be done while the law condones smacking."
Des Mannion, head of service for NSPCC Cymru/Wales, said: "We welcome the Welsh assembly vote in favour of bringing forward legislation to provide children with the same legal protection from assault as adults.
"This is a real example of Wales leading the way in giving Welsh children the kind of protection that other children in the UK don't enjoy."
He said the current law was "ambiguous", adding: "We encourage the Welsh government to bring forward this legislation as soon as possible and continue its work to support parents by promoting positive, effective and non-violent methods of disciplining children."
First Minister Carwyn Jones has said it is the view of Welsh ministers that it is possible for the assembly to amend the criminal law and "end the availability of the defence of reasonable punishment for those cases where it still applies to an offence of assaulting a child".
But Welsh Affairs Committee chairman David Davies said the issue should be referred to the Supreme Court if AMs vote in favour of a ban.