The principal of a high school where about 30 students accessed internet pornography sites says schools need to update their security software constantly and review their internet policies.
Otaki College principal John Kane said yesterday that the school already had rules and policies for internet use, student internet-user agreements and securitysoftware.
However, after the pornography incident he was reviewing the policies and looking at other filtering software.
Mr Kane said about a dozen year nine and 10 pupils (third and fourth formers) had viewed sites involving "nasty" and "pretty shocking" illegal sexual activity.
The rest saw less disturbing but still offensive images.
The pupils looked up the sites on school computers during free periods, at lunchtime and, in a couple of cases at least, during class time.
They were found out last week when a staff member noticed pupils huddled around computers, Mr Kane said.
It was difficult to prevent students viewing off-limits websites, but schools needed to be vigilant.
They needed to stay abreast of rapidly developing technology through continually reviewing and updating policies and software.
Some children were still likely to try to access off-limits internet sites, he said.
"Staff need to look for the signs - groups of students clustered around a screen, furtive looks and screens swivelled so the teacher cannot see them." In the case of the Otaki College students their parents had been told, counselling offered and in most cases internet privileges withdrawn.
"For most of these students the biggest outcome has been having to discuss this issue with their parents," he said.
Earlier, Mr Kane said no students had been stood down or suspended because there was no evidence that anyone had maliciously exposed their classmates to the websites.
Internet Safety Group education spokeswoman Claire Balfour said adults should not underestimate the trauma some young people suffered when they saw vicious and violent internet pornography.
Some website developers misspelled the names of popular children's toys or television series in order to lead children to pornographic sites, she said.
