The complaint was about aspects of the pamphlet that compared the Conservatives and NZ First over issues including "Trust", "Referendum", "Anti-Smacking Law" and "Alcohol Reform".
The authority upheld the complaint only in relation to the Alcohol Reform section and its reference to five "key recommendations" of the Law Commission. The recommendations that were "key" were the opinion of the party, and the pamphlet should not have presented them as from the Law Commission, the ruling said.
"The Complaints Board agreed the statements contained a substantive error of fact, and therefore breached the threshold to be likely to mislead the consumer."
Mr Peters said the decision showed that Mr Craig was "manipulative".
"This was not robust political debate but a deliberate attempt to sway voters with manipulative information." He disagreed with the authority that only the section of the letter about Alcohol Reform was factually incorrect.
"I can understand their view, but we take it as being a totally manipulative document, the whole lot. But I'm not going to judge to authority. They regarded it as robust. I don't regard it as robust. It's just dirt.
"I don't think the public's going to be persuaded by it."
But Mr Craig said he was pleased with the ruling.
"When you look at all the things they complained about, the only thing upheld is one little wording change." He said the wording would be fine if they removed the words "Law Commission" and replaced them with "The 5+ Solution from Alcohol Action NZ".
"That is so minor. It was a major attempt by Winston Peters to discredit the whole thing and he's failed horribly.
"Probably the comparison on trust and referendums, the anti-smacking law and legal highs are far more important in voters' minds (than alcohol reform)."
Mr Craig said he didn't believe the sudden resignation of his press secretary had anything to do with the authority's decision.
"She has nothing to do with the preparing of that material in any way. We've had two ASA complaints about election material but that doesn't involve her directly."
He did not think it would hurt the final day of his campaign, but admitted that his press secretary walking away was "not ideal".
"Obviously it's not what you would want to happen, out of the blue. There are some people upset by the suddenness of it all, but in the end it hasn't affected anyone's vote."
Mr Craig's lawyers had tried to push back the ASA decision, saying it was politically motivated and they did not have enough time to respond -- which would have seen the decision come out after the election.
But the authority rejected this.
"The matters raised were not just between two political parties with differing views, but rather matters with a broader public interest directly related to the upcoming general election.
"The chairperson said the proper procedures had been followed, the chairman had not misinterpreted the evidence and there had be no breach of natural justice in the chairman's ruling."
Peters: It was a 'manipulative document'
Mr Peters said he disagreed with the authority that only the section of the letter about Alcohol Reform was factually incorrect.
"I can understand their view, but we take it as being a totally manipulative document, the whole lot.
"But I'm not going to judge to authority. They regarded it as robust. I don't regard it as robust. It's just dirt.
"This a guy that says he's going to clean up politics, and that was a full-scale personal attack, basically. I don't think the public's going to be persuaded by it."
He said a vote for the Conservative Party was "a wasted vote".
