The chief censor, David Shanks, says parents should be aware that their children are watching season two of the Netflix series 13 Reasons Why, and watch it themselves.
Season two of the teen drama launches on Friday, following the first season which was a highly controversial global hit.
"This series deals with issues such as rape and suicide in a way that would have been unimaginable even just a few years ago," Mr Shanks told Seven Sharp.
His office had contacted the programme saying he needed to come on Seven Sharp.
"We have a vulnerable population of young people in this country, and my concern is this could have impacts on those people," he said.
The first series of 13 Reasons Why came out a year ago, but because it was on a streaming service, the chief censor wasn't required to view it or classify it before Kiwi audiences saw it.
And it soon became clear the show was causing harm for some, as Shaun Robinson, Mental Health Foundation chief executive explained.
"We know for certain that people were put into really serious distress, potentially heightened their own risk of suicide, and in some cases led to people actually having to be hospitalised," he said.
The chief censor exercised his power to call in the show and created a new classification, RP18.
"This classification requires that parents are aware that children are consuming this product and to help them out with that," Mr Shanks said.
He and the Mental Health Foundation are working together to create support for young viewers and their parents.
"We recognise that some teens will not want to watch this show with their parents. But parents should be aware that they're watching and watch it themselves," Mr Shanks said.
For help and advice please contact the following:
Need to talk? 1737 – Free call or text 1737 any time for support from a trained counsellor
Lifeline – Free call 0800 LIFELINE (543 354), or free text HELP (4357)
Youthline - 0800 376 633, free text 234 or email firstname.lastname@example.org
Samaritans – 0800 726 666
Healthline – 0800 611 116
Depression helpline: 0800 111 757 or free text 4202 or www.depression.org.nz
The Lowdown: A website to help young New Zealanders recognise and understand depression or anxiety. www.thelowdown.co.nz or free text 5626
SPARX.org.nz – Online e-therapy tool provided by the University of Auckland that helps young people learn skills to deal with feeling down, depressed or stressed
OUTLine NZ – 0800 688 5463 for support related to sexual orientation or gender identity