A One News report of Clayton Weatherston's murder trial has been found to breach broadcasting standards relating to good taste and decency, children's interests and violence.
Hastings mother Sharon Coates complained to the Broadcasting Standards Authority (BSA) about the July 13 news item, saying it contained Weatherston's graphic evidence of how he killed Sophie Elliott that was "sick and disgusting".
She also complained that One News the following night broadcast foul language read out by the crown prosecutor from Ms Elliott's diary.
Ms Coates said neither item was preceded by a warning and she had turned her television off when her children became upset by Weatherston's description of stabbing Ms Elliott.
TVNZ responded that the word "f...ing", used three times in the July 14 item, should have been edited out and pointed out that it broadcast an apology to viewers the following night.
But it said an obligation to provide a fair and accurate portrayal of what was said in court and its lengthy introduction gave viewers adequate warning of the type of material that was to be included in Weatherston giving his evidence.
It was important New Zealanders understood the offensiveness of his crime and "sanitising or censoring" the evidence would have distorted the issue.
The BSA found that TVNZ's apology for the July 14 item was appropriate and sufficient.
But it considered viewers would have been unprepared for the level of explicit detail in the July 13 item.
"The item's introduction was insufficient to signpost the grisly and unpleasant details relayed by Mr Weatherston," the authority said.
The BSA found One News had breached the standards of good taste and decency, did not adequately consider the interests of child viewers and did not exercise sufficient care and discretion when dealing with violence.
But it said choosing footage to include in reports in such an unusual trial would have been a difficult editorial decision. It was also important for the public see Weatherston giving evidence, in order to reflect events accurately.
"The authority finds that the publication of its decision is sufficient in the circumstances and expects that it will provide guidance for TVNZ when reporting on similar issues in the future," chairwoman Joanne Morris said.
The BSA upheld another viewer's complaint about the lack of warning before One News' July 13 item, but did not uphold complaints against the broadcaster's coverage of the Weatherston trial on July 9.
