McIvor had said: "But if you are Māori and you have some great contacts in the police …"
The online article was later updated.
The council noted "ZB's handling of the complaint was poor" and that the opinion piece was online for over a month before it was edited.
"When ZB did address the Media Council complaint it still referred to issues that are covered by the BSA's principles, but not ours."
The complaint about the comment was upheld by the Media Council on Principle 7, Discrimination and Diversity.
The council said no other ethnicity, aside from Māori, was mentioned in the column and this could "enhance any unconscious bias in others reading the article".
"The comment regarding Māori in both the original piece and the updated one could be said to be denigrating Māori and inferring that only Māori behaved in such a way. The council understands the particular people McIvor was referring to were Māori. However the focus of the column and the author's criticism, was their breaking of the Covid rules and has nothing to do with their ethnicity."
McIvor apologised for her "poor choice of words" .
"I was meaning to be critical of the police iwi liaison officer who was reportedly taking people through the border; It was not my intention to incorrectly stereotype a whole community and I apologise for the hurt my words caused.
"I try to be aware of context, but there is always opportunity to do better and be more mindful."
In a statement, NZME said it accepts the findings of the Media Council and the company "apologises unreservedly".
"In light of the different circumstances regarding this complaint, we have reviewed and updated our processes to better ensure all complaints are handled through the correct channels."