Speaking at the National Cyberbullying Conference, Geoffrey Shannon said the law needs to keep pace with technology and the current law in the area dates back to 1997.
Mr Shannon said a child-centred approach is required to tackle the issue.
He said along with the State, schools also have an obligation to be proactive in the area of preventing cyber bullying.
Addressing the same conference, Simon Milner, Policy Director for the UK, Middle East and Africa for Facebook, said with a community of 1.3bn people, some relationships go wrong, and there are some who want to harm others.
However, he said Facebook has clear policies about what is not allowed, tools to resolve cyber bullying issues and help if required at every stage of the process.
He said most allegations of cyber bullying on Facebook relate to photos, typically photos that someone does not like.
He said it was now possible for people to resolve problems with Facebook content quickly between themselves, and where matters cannot be resolved there are community operations to help.
He said there are also mechanisms for professionals to escalate issues if they are not being handled properly, although in response to a question he said it was not possible to have a mechanism for school principals to directly contact Facebook in urgent cases.
Mr Milner said the company was always trying to make it as simple as possible for people to know who they are sharing with.
Also speaking at the conference, Clive Byrne of the National Association of Principals and Deputy Principals said key measures are needed to tackle the cyber bullying problem, including a dedicated classroom module at junior and senior cycle.
He said an increase in funding to enable teachers and parents to be trained was also a priority, as well as the development of school guidelines for parents concerned about the problem.
The conference is organised by the National Anti-Bullying Research and Resource Centre at DCU and Bully4u.