Nine in ten parents say their child has been a victim of online bullying, according to Bitdefender.

A survey of 1,740 web users with children by the security firm revealed over half of those with kids that have been bullied online said their child had been "very affected" by the experience. Furthermore, 19 percent of parents revealed they had sought specialist help for their child.

Cyberbullying, defined as threatening, harassing, humiliating, embarrassing or otherwise tormenting others online.

"The results of this study should send out a very strong message to parents – it's more vital than ever to take steps towards protecting children from cyber bullying," said Sabina Datcu, Bitdefender's E-Threats Analysis and Communication specialist.

"Parents need to understand the necessity of installing Parental Control software and of monitoring their teenagers' activity on social networks and on the Internet in general."

According to the anti-bullying charity Kidscape, parents should encourage their child to alert them if they are experiencing online bullying. They should also report any instances of bullying. For example, a number of sites including social network Bebo offer a 'Panic button' that provides access to advice and support from the Child Exploitation and Online Protection (CEOP) Centre along with nine other different sources of help including Childline and Beatbullying, as well as a way to report the problem. Meanwhile Facebook has its own dedicated reporting system that lets social networks flag up any abusive content.

Furthermore, parents should become familiar with technology and the internet themselves, to ensure they have a better idea of what happens online and the types of sites a child could be visiting.