Prime Minister John Key has stopped short of criticising Christine Rankin for her renewed criticism of the anti-smacking law - but he has made it clear he will not tolerate any "active campaigning" by the families commissioner before the referendum on the law.

In an interview published in Investigate magazine, Ms Rankin attacked the anti-smacking law, saying it had traumatised families.

She said it was a parent's right to smack as a form of discipline.

Mr Key has forbidden Ms Rankin to campaign on the anti-smacking law referendum.

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