Cyber-savvy students are abusing fellow pupils on teen websites and accusing senior teachers of widespread sexual abuse - and many of the schools know nothing about it.

On one website, two teachers from one elite Auckland school have been named and accused of sexual abuse of students, while on another site "13-year-old students" have posted photographs of themselves in bikinis asking to be rated.

The websites follow ongoing problems with text bullying, which have already contributed to the death of two teenagers this year.

The School Trustees Association has flagged the websites, uncyclopedia and bebo, as the latest form of "large-scale harassment", but surprisingly many schools have heard nothing about them.

The Herald on Sunday found the following on the two sites:

* death wishes and accusations against specific, named teachers - including a wish that two intermediate school teachers would die by swallowing a paintbrush or faeces - and allegations of sexual abuse by senior teachers at a top Auckland school

* threats and vicious name-calling against students - one student was told he had "lost the ability of friendship" and was a "corrupt freak of nature"; another was named and accused of killing his mother; girls traded insults and threatened to beat each other up

* the offer of sex with a 14-year-old Epsom Girls' Grammar School student with "no strings boys - none at all". The girl's name and cellphone number were provided but when contacted by the Herald on Sunday she said she was unaware of the message.

Students from at least 15 schools, including King's College, Auckland Grammar School, Diocesan School for Girls, St Cuthberts School, Dilworth College and St Peters College, have been regularly using the uncyclopedia website while the bebo website is used by students at virtually every New Zealand school, including intermediate and primary schools.

The Epsom Girls' Grammar School student who was offered up for sex said she and her friends were "obsessed" with bebo but she was sometimes scared to go to school because of the bullying online.

"It's horrible. Like, 'you're stupid, you're gay, I'm going to beat you up at school', that sort of stupid stuff."

The youngest person she had seen on the site was just 10 years old.

"Everyone goes on it every day, people are obsessed with it. Everyone gets bullied on that website."

She was surprised and scared that her name and cellphone number had been posted - along with a torrent of abuse - on uncyclopedia, but said it was common for students to add full names, pictures and phone numbers to their personal pages.

Uncyclopedia was a parody site promoted as the "content-free encyclopedia that anyone can edit".

Bebo also became popular this year, but was much more interactive - hundreds of New Zealand students had homepages, on which many posted their names, photographs, email addresses acnd phone numbers.

They could then chat and comment on one another.

Many conversations were sexual or aggressive, and many users said they were just 13 or 14 years old.

Some posed topless or wearing bikinis or bras. One girl, who said she was 15, wore a French maid's outfit.

Chris Haines, president of the school trustees' association, last week used a newsletter to warn schools of the sites.

"These websites appear to be linked internationally and invite young people (or those purporting to be young people) to enrol under the name of their school, set up their own personal page and interact with others on the site."

Mr Haines urged schools to contact the Ministry of Education's internet watchdog, NetSafe and reminded trustees of their requirement to provide a safe physical and emotional environment for students.

Roy Kelly, principal of King's College, said the uncyclopedia website was "nasty", putting it on a par with text bullying and playground violence.

A handful of students were named on the King's College page, which appeared on February 23. "What is put on the website is beyond our control," he said.

However, once students realised management knew of the site, use dropped dramatically.

The school's IT department checked it regularly and removed offensive content. It could not be accessed from a school computer.