A cell phone ban has helped reduce bullying and cut the number of student fights at a Wanganui high school.
Wanganui City College principal Peter Kaua said the school had worked hard to reduce cyber bullying in the past four years.
The cell phone ban had made a huge difference.
"Cell phones were sometimes the source of the problem.
"The text would go round and say 'there's going to be a fight at such and such a time'.''
Police are investigating two separate incidents of cyber bullying after videos of students fighting were posted on social media sites.
Students from at least three Hamilton schools were filmed in fights at a park last Monday. The footage, taken on a digital camera phone, showed girls and boys brawling and was posted on YouTube.
Further north, a video showing a 14-year-old Northland student being beaten up by classmates was posted on Facebook and YouTube.
The Ruawai College student was attacked in the school bathrooms while a group of students looked on and filmed.
Two students, aged 15 and 16, have been thrown out of the college and face charges in the Youth Court. Two younger students have been referred to Police Youth Aid.
Principal Stephen Fordyce said the "criminal event'' happened in September and had caused great distress.
"The police were informed immediately [after] we became aware of the seriousness of what had occurred.''
NetSafe executive director Martin Cocker said bullies used online videos to exert superiority.
"The bullying is about exerting power over another person.
"Posting a fight of where you win, or the other person is a victim, increases the power imbalance between you.
"It's a logical bullying system.''
Young people often failed to understand the repercussions of bullying, Mr Cocker said.
In one of New Zealand's worst cases of cyber bullying, 15-year-old Wanganui schoolgirl Robin de Jong was filmed being chased down and assaulted by another student last year. Footage of her attacker punching and kicking her until she was unconscious was captured on another pupil's cellphone.
Rotorua teenager Hayley-Anne Fenton took her own life four years ago after receiving abusive text messages from her boyfriend's wife. The case sparked calls for change to social media regulation.
The Government is currently considering a proposed law to crackdown on internet bullies.
It includes the formation of a Communications Tribunal which would deal with online harassment cases. Offensive posts on Facebook and Twitter and hurtful text messages would become a new criminal offence.
Rotorua Lakes High School principal Bruce Walker said cyber bullying was a community problem.
"It's happening at home, it's happening at school and it's happening in the workplace.''
Mr Walker stressed that anything posted online lasted forever.
"In the past we've had issues of silly fights that then get filmed.
"Sometimes when we've investigated, we've found that the fights are pretend and just a set-up,'' he said.
Mount Maunganui College principal Russell Gordon said schools needed to cater for the iPod generation by teaching online safety to address cyber bullying and promote a safe school environment.
"We had an organisation come in and speak to our year 9 and 10s...and our seniors about online etiquette earlier this year.''
Students had to understand that whilst it was not a right, it certainly was a privilege to be online and have access to technology, Mr Gordon said.
* At least one in five New Zealand high school students have reported being victims of cyber bullying.
* Cyber bullying includes use of the internet, mobile phones or other technology to hurt, harass or embarrass another person.
* Vodafone customers can use its Blacklist service to block certain people from messaging them.
*If someone has threatened to hurt you physically, contact police
* Call 0508 NETSAFE for more information or go to www.netsafe.org.nz
- additional reporting Kieran Campbell