A controversial Netflix show has been given a new rating by the censor's office.

LISTEN ABOVE: Chief censor Jared Mullen spoke to Rachel Smalley

13 Reasons Why - which follows the life of a teenage girl who commits suicide and explores the reasons she did so - sparked concern over whether its content is appropriate for young people.

The NZ Office of Film and Literature Classification says Netflix has to display a clear warning in each episode.

It's been given an RP18 classification - meaning the show should only be watched by those younger than 18 if a guardian is present.

An RP16 or R16 was discussed, but it was decided that would not address the harm caused to 16 and 17 year olds who are statistically at greater risk of suicide.

The classification office's most immediate concern, and why 13 Reasons Why has been censured, was how teen suicide was discussed and shown in the series, according to a blog post on its website.

It said the show represented suicide at times as not only a logical, but an unavoidable outcome of the events.

"Suicide should not be presented to anyone as being the result of clear headed thinking... most people who experience suicidal thoughts are not thinking rationally."

The office said the series ignored the relationship between suicide and the mental illness that often accompanies it.

"People often commit suicide because they are unwell, not simply because people have been cruel to them."

The Sexual Abuse Prevention Network was also concerned the series did not offer any positive examples of appropriate responses to rape disclosures.

Mental health advocates have expressed extreme concern about what effects 13 Reasons could have on teenagers, given that New Zealand has one of the highest youth suicide rates in the OECD.

However, the classification office also said the show had "significant merit", and "addresses issues that are highly relevant to young people, including suicide, sexual violence, bullying, and slut-shaming".

Several groups have also praised the issues raised.

The Mental Health Foundation New Zealand said it presented a good opportunity to raise awareness about youth mental health issues, but that these conversations needed to be informed and safe.

Additional reporting by NZ Newswire 

If you need support and information about suicide prevention, you can contact:

- Lifeline's 24-hour telephone counselling service on 0800 543 354
- Depression Helpline (8am to 12 midnight) - 0800 111 757
- Healthline - 0800 611 116
- Suicide Crisis Helpline (aimed at those in distress, or those who are concerned about the wellbeing of someone else) - 0508 828 865 (0508 TAUTOKO)
- Youthline - 0800 376 633, free text 234 or email talkyouthline.co.nz
- Kidsline (aimed at children up to 14 years of age; 4pm to 6pm weekdays) 0800 54 37 54 (0800 kidsline) ]