The Internal Affairs Department has begun working alongside Internet service providers to block access to websites dedicated to child pornography.

Censorship manager Steve O'Brien says the department has drawn up a list of more than 7000 websites that host illegal material. Two Internet service providers agreed to block access to the sites in a trial which has been running for several months but which is still at "the very early stages".

Mr O'Brien says the idea is based on very successful approaches to combating child porn in Norway and Sweden.

If the trial is expanded, people who try to access sites identified by Internal Affairs as hosting child porn may see a webpage telling them the site has been blocked and inviting them to contact the department if they have any queries.

At the moment, they will find the sites will simply not load, he says.

During September and last month, the two ISPs that are part of the trial processed six million website requests from customers, of which 3351 were blocked.

Mr O'Brien says Internal Affairs will not try to identify who tried to access the censored sites, because that would defeat the purpose of what it hopes to achieve.

"We are trying to show to average New Zealanders that we are trying to prevent harmful material going on to people's screens, not waving a big stick at them."

Internal Affairs is not blocking sites that are "borderline", he says, but only "known child-abuse sites".

Mr O'Brien says the scheme does not require legislation, relying instead on the goodwill of ISPs. "Once we're satisfied with the technical mechanisms, we'll invite a number of ISPs to increase the size of the trial and take it from there."

The "beauty of the approach" is that ISPs themselves do not face additional costs filtering websites for illegal content, he says. Any delays to legal web surfing caused by checking web requests against the list of banned sites would not be noticeable to computer users.

Mr O'Brien says the list of banned sites is updated daily, since most "dedicated" child porn sites tend to change address every couple of days. International cooperation with overseas censors is likely, to keep the list up to date.

This does not address the issue of file-sharing over peer-to-peer networks and is not a "be-all and end-all", but if enough countries adopted the tactic it could become harder to make a business out of selling child porn, he says.

- The Dominion Post