Wanganui City College principal Peter Kaua said the school had worked hard to reduce cyber bullying in the past four years.
The ban on cell phones 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."
Nationally, 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 on Monday afternoon. 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."
Speaking yesterday, Mr Kaua stressed the importance of creating a safe school environment: "We try to instil school values and reinforce the rules and reinforce that we're here to make sure [students] are safe at school.
"We've had a few little scuffles but we haven't had the scale of what it used to be like."
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."
Young people often failed to understand the repercussions of bullying, Mr Cocker said.
In one of New Zealand's worst cases, 15-year-old Wanganui schoolgirl Robin de Jong was filmed being chased 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 life four years ago after receiving abusive text messages from her boyfriend's wife. The case sparked calls for change to social media regulation.
Coroner Wallace Bain found the overarching cause for her death was the "shocking bullying" texts she had received.
The Government is considering a law to crack down on internet bullies. It includes the formation of a Communications Tribunal to deal with online harassment cases. Offensive posts on Facebook and Twitter and hurtful text messages will become a criminal offence.
- Additional reporting Kieran Campbell APNZ
