An internet safety group is calling for the government to introduce tight controls on internet and cellphone chat rooms after revelations paedophiles were preying on children through phone texting.

Vodafone shut down its mobile phone chatroom for children after discovering paedophiles were trying to meet and potentially have sex with them.

The men have been lying about their age on the chatroom, called Teenzone, and there are no safeguards to stop them doing so.

Director of the Internet Safety Group Liz Butterfield says children can put themselves in quite serious situations through chatrooms on cellphones and the internet.

She says about 25% of teenagers with cellphones are texting people they don't even know.

Butterfield says the New Zealand government should follow Britain in ensuring there's an age verification on cellphone chat services.

A spokesman for Vodafone says it shut down the chatroom as soon as it became aware that men were preying on youngsters who used it, wanting to meet them.

Kieren Cooney says teenagers and children could chat to each other anonymously through their cellphones and it's terrible they were being taken advantage of.