Family First has released a documentary challenging a Government review of changes to the child discipline laws.
The review found that parents are not being criminalised or unduly investigated for lightly smacking their children.
Psychologist Nigel Latta, who voted against the anti-smacking law in a referendum in 2009, was a member of the panel.
However, Family First says the documentary contains evidence that the review contained errors and it has no credibility.
Wellington criminal barrister Michael Bott also describes the review as a "rubber stamping" process.