A new crackdown on cyber bullying was unveiled by the government on Friday in a bid to stamp out the growing problem in schools.

The new measures aim to protect pupils and teachers from abusive text messages, phone calls and emails and offensive or violent video clips posted on the Internet.

More than a third of teenagers aged between 12 and 15 have fallen victim to cyber bullies, according to government figures. Unions say teachers have been belittled and bullied by offensive comments on the Internet.

Ministers hope to tackle the problem with an online anti-bullying campaign. The government issued tips on how to beat the bullies and has released a video for teachers.

Schools Secretary Ed Balls said any form of bullying was unacceptable.

Cyber bullying is a particularly insidious type of bullying as it can follow young people wherever they go and the anonymity that it seemingly affords to the perpetrator can make it even more stressful for the victim, he said in a statement.

Bullying evolves as society and technology changes, so schools need to get to grips with newer forms of bullying and the different impact these have on the victim.

Teaching organisations welcomed the new guidelines.

The National Association of Head Teachers' general secretary, Mick Brookes, said they were timely to make sure it does not become a growing problem and it is dealt with.

This form of bullying will not be tolerated in any shape or form. It is the same as playground bullying but it can, in some instances, be more damaging, he said.

National Union of Teachers general secretary, Steve Sinnott, said new technology had opened up a myriad range of opportunities for bullies.

He said it was the first time that such clear and in-depth guidance on homophobic bullying had been published.

Homophobic bullying is the favourite weapon of bullies who pick on pupils who appear different or vulnerable, he said.

Good experienced teachers can be driven out of the profession by homophobic taunts.

This guidance should not be left to gather dust on shelves.