The broadcasting watchdog has found TVNZ breached standards by playing an episode about serial killer Ted Bundy when about 200 children would have been watching.
The Broadcasting Standards Authority (BSA) decision ruled the station breached children's interest standards and programme information when it aired a rerun episode of current affairs show 20/20 about the serial killer at 9am on a Sunday.
The episode presented potentially distressing and disturbing content without an audience advisory or warning, and should have been broadcast during the M rather than PG timeband, the BSA found.
The complainant said her young children accidentally ended up on the wrong channel and watched part of the gruesome episode instead of TV2 children's show, What Now.
TVNZ estimated about 200 children were exposed to the 9am repeat, which screened between episodes of Topp Country and Marae on TVNZ 1.
The BSA ordered TVNZ to pay costs to the Crown of $750.