The producer of TV2's Sensing Murder programme says he had no idea reruns of the six-year-old shows were to be broadcast, and if he had, he would have informed the families.
Some of the families, including murder victim Jane Furlong's mother, Judith, have expressed shock and upset at the programmes suddenly appearing on television this month.
Sensing Murder follows Kiwi psychics Sue Nicholson, Kelvin Cruickshank and Australian medium Deb Webber, as they investigate high-profile unsolved cases.
The show involves two psychics being given a photo of the victim on separate days. They then use the photo and their psychic abilities to retrace the victim's steps.
The show's producer, David Baldock, told the Herald he was "equally concerned and sad that neither the families nor myself as the producer were notified that the series was going to be rerun".
"From Ninox Productions perspective and Ninox Television's perspective we would have expected to have been notified and we would have notified the family, so I think that's a real discourtesy, particularly on a subject matter that it is."
Ninox no longer held the rights to Sensing Murder, he said, as it did not exist as a production company anymore. However, he said former staff still had all the contacts for the families and would have been happy to notify them.
"We only did the show with respect for the families ... I'm a documentary maker, that's my profession, I would never do anything to undermine that reputation, and I still stand by the work ... But it is imperative, and it is important that particularly on subject matters like this, that the families are notified when the programme's going to be rescreened."
Mr Baldock said he was proud of the show which always recounted factual information known about the cases which then got put back into the public arena.
"I think the work that the psychics did was fantastic ... I'm very very proud of the show, the show has had huge impact."
A TVNZ spokeswoman said repeats of Sensing Murder season 4, which originally aired in March 2010, will continue to play throughout January and into February when its new season programming begins.
She said there was no need to let affected families know about the reruns as they held the licence.
"Everyone signed up to repeats when the programme was being made. The series remains under licence to us, so there's been no need to alert the families."