The Prime Minister says he has confidence in the findings of a three-person review of smacking legislation presented to him last year, following criticism by a group at the centre of the review.
Television psychologist Nigel Latta, Police Commissioner Howard Broad and Ministry of Social Development (MSD) chief executive Peter Hughes carried out the three-month review and concluded that none of the cases highlighted by pro-smacking lobby Family First stacked up.
Family First had used them as evidence that the repeal of Section 59 of the Crimes Act, effectively banning smacking for the purposes of correction, had failed.
Mr Latta reviewed several individual cases highlighted in the media and said he was personally reassured the law change made no difference to the way the police and social workers did their job.
He said Family First was often not given the full story when it championed parents it felt had been prosecuted for minor child discipline offences.
Family First director Bob McCoskrie said information obtained under the Official Information Act shows the review contained "glaring errors".
It did not follow its terms of reference, focused on the alleged actions of parents and misrepresented basic facts, he said.
The review failed to look thoroughly at the cases and "good parents have indeed been taken through hell as a result of the anti-smacking law and they are just the tip of the iceberg".
"John Key must now deliver on his pre-election promise to amend the law if he saw good parents being criminalised," Mr McCoskrie said.
Mr Key, who has repeatedly said the law was working the way Parliament intended, said he was happy with the review.
"The team made judgements based on all available information, and I accept and have confidence in the findings.
"After the review, MSD said that changes would be made by Child Youth and Family to the way parents are dealt with, and I'm pleased to say those changes have been made," Mr Key said.
The latest issue of Investigate magazine says the smacking review was "effectively a farce".
"Latta's review got its facts wrong, and based its misleading and defamatory findings simply on police or CYF complaint sheets, not the outcome of court cases after the evidence had actually been tested," editor Ian Wishart said.
"To fail to fully investigate cases because you have misunderstood your own terms of reference, and then to accuse parents of not being honest, is breathtaking arrogance."