A new survey shows children are unsupervised for 80% of the time they are online.
Up to 300 ten to 15-year-olds were polled by Niall Mulrine, a computer expert, who gives anti-bullying lectures.
Another study of more than 200 16- to 18-year-olds found almost all of their time online was unsupervised.
The research has sparked concern over the opportunities afforded to cyber bullies to abuse their victims.