All school boards of trustees are to be told to review anti-bullying policies after graphic incidents reported last week.

Prime Minister John Key said he expected all boards to meet their principals, who would in turn meet staff and pupils to discuss bullying.

He wanted a "nationwide conversation" on how to reduce bullying. He also expected that Education Review Office audits of schools would reflect schools' anti-bullying plans.

"I worry about bullying," Mr Key said at his post-Cabinet press conference yesterday.

"I worry about youngsters going to school and being intimidated by others and it's thuggish-type behaviour that needs to stop and we want to send a strong message about that.

"I have very high expectations that youngsters will be able to go to school and enjoy being at school in a safe environment and if they are subject to bullying, I expect that to be dealt with."

Boards of trustees were required by law to provide a safe environment.

Wide coverage has been given to two recent video clips of bullying - that of Sydney schoolboy Casey Heynes, who lashed out against another boy who had repeatedly bullied him, and images of 15-year-old Wanganui schoolgirl Robin de Jong being attacked and kicked until she was unconscious by a classmate, who has since been expelled.

Mr Key said he had asked Education Minister Anne Tolley to write to all boards to remind them of what their responsibilities were and to convene a meeting of experts to see if New Zealand schools had best practice in place to counter bullying.

"We need to understand what happens when bullying gets out of control and that is, taken to the extreme, some youngsters take their own life.

"I'm not going to sit back and let that happen without at least trying to improve the environment."