Young people need to be taught about the dangers of making inappropriate remarks on a public forum, says the Secondary Principals' Association.
Police are investigating comments made by Christchurch students from Burnside High School on the social networking website Facebook.
The comments, which were posted on a web page that has since been taken down, included threats and derogatory statements directed at the school's new principal, Warwick Maguire.
The president of the association Peter Gall says the comments could be defamatory.
Mr Gall says educating young people about defamation is the job of teachers, parents and the media.