The Media Council has found RNZ breached its principles of privacy and confidentiality when a carelessly chosen pseudonym was used in a story.
The ruling followed a complaint about a story, published in March. It reported a woman's concern that her child, and other babies born during the pandemic, were living semi-reclusive lives and were missing out on social interaction.
When she suggested the story to RNZ, she made it clear she did not want to be identified for personal reasons.
But the pseudonym used by the reporter was very similar to her real name. It was just one letter different. The story also reported her locality and her son's age.
The Media Council said the choice of pseudonym was careless.
"It is understandable that the complainant believed RNZ had failed to honour her request that she did not want her name used in the article and that her right to privacy had not been respected.
"The fact that some people, or even one person, identified her proves her privacy was breached.
"On the face of it this was not a story where it would be expected that harm would be done by publication, but as we have already noted we accept the complainant's statement that the story had caused her harm."
The Media Council noted that the reporter apologised immediately when the issue was raised, and the story was amended quickly.
"It may seem that the careless choice of a pseudonym was not a major error - it was a slip that many would forgive following a swift apology and correction. But even small mistakes can have consequences and cannot always be absolved with an apology."
"Given the express failure to honour a promise not to name, the correction in this instance does not defuse the mistake. Damage had been done - the complainant had been identified," the Media Council said in its ruling.