The Secondary Principals' Association says installing cameras in school washrooms is becoming common practice in secondary schools.
The association's president, Patrick Walsh, says it is a sad indictment of society that secondary schools across the country are increasing security surveillance against their own students.
Wainuiomata High School, near Wellington, has confirmed it will install cameras in toilet washrooms to stop vandalism and deter smoking.
The announcement was posted on the school's Facebook site and, despite one privacy concern, the response from past and present students has been positive.
Wainuiomata High School's decison comes despite a Privacy Commission warning that installing cameras in such locations may breach student privacy.
A spokesperson for the Privacy Commissioner says only an extraordinary set of circumstances can justify putting up cameras where people might be changing their clothes.
The spokesperson says the commissoner has received several enquiries from the public about CCTV in schools in the last couple of years.
The chairperson of the Council for Civil Liberties, Batch Hales, says it is an infringement of human rights. He says schools need to stop acting as prisons, and starting acting as safe havens for students.