A third of high school students admit deliberately sending emails or instant messages knowing they will upset the person receiving it.
The statistic is one of many sobering revelations in a survey highlighting the level of cyberbullying our teenagers confront on a daily basis.
Victoria University's Youth Technology Use Project, which surveyed 868 students from 18 high schools last August, found a troubling culture where name-calling and being left out is rife and pupils face an additional onslaught online.
The survey found boys and girls took part in cyberbullying, with more than half the boys saying they had posted about someone else to make others laugh and nearly one in three boys had sent a message to anger a person or make fun of them. One in four girls and one in five boys said they had posted an embarrassing picture online without permission.
On the receiving end, a third of all girls and a quarter of boys said they had been the victim of a person posting something to make them upset or uncomfortable.
Nearly one out of two female students had an embarrassing photo posted on social media last year against their will. One third of all girls said it happened a couple of times.
One fifth of boys surveyed said they had had an embarrassing picture posted a couple of times.
But cyberbullying hasn't replaced other verbal and physical bullying.
Nearly two-thirds of girls said they had been excluded by other students in the previous four weeks.
Boys reported an even higher incidence of name-calling and a concerning level of physical violence between peers.
Auckland University Professor John Fenaughty, who has written a doctoral thesis on the nature of cyberbullying in New Zealand, said cyberbullying and face-to-face bullying often happened at the same time.
The multiple types of bullying was more likely to cause distress.
There was still a lot to be done to support schools and workplaces to reduce bullying in the first place.
He said the Youth 2000 research series indicated there had been very little change in reported bullying rates over the past decade.
Concerns were now shifting to whether cheaper and better mobile devices had enabled more frequent and diverse forms of cyberbullying.
"Cyberbullying is a very real issue for young people here. This issue seems to persist and with the proliferation of cheaper phones and plans it may get worse before it gets better," said Mr Fenaughty.
Victoria University Professor Vanessa Green said we didn't know the true extent of the problem as teenagers often feared that admitting being bullied to an adult would lead to their phone being confiscated.
The possibility that cyberbullying was vastly under-reported warranted further investigation, she said.
Ms Green said her research showed most children being cyberbullied were also being bullied in other, more traditional ways.
"So you've got this kind of added dimension and stress for the student because they're going along knowing quite well that that anonymous text or email or image is quite possibly being sent by the person sitting next to them in class."
Ms Green was now researching bullying behaviours of preschoolers to try to tackle anti-social actions from day one.
She said international research showed children as young as 3 exhibited social exclusion behaviours, whether for having the wrong item in their lunchbox or deciding they don't like a child and preventing others from playing with them.
The local research would provide a baseline before implementing anti-bullying programmes such as the Finnish KiVa system in early childhood to try to turn the tide of abuse for future generations.
Where to get help:
• In an emergency: call 111
• Lifeline: 0800 543 354 (available 24/7)
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• Youthline: 0800 376 633, or text 234 (available 24/7) or firstname.lastname@example.org or live chat (between 7pm and 11pm) http://livechat.youthline.co.nz/mibew/chat?locale=en&style=youthline
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155 (weekdays 11am to 5pm)
• NetSafe: 0508 NETSAFE (0508 638 723), www.theorb.org.nz