More schools are considering installing surveillance cameras in bathrooms used by students, says Privacy Commissioner Michael Webster.
The commission had seen an increase in inquiries from schools wanting to use surveillance technology to reduce problems such as vaping and bullying, Webster said.
However, bathroom surveillance could pose a privacy issue, he said.
"We understand the concerns schools have about student safety, but equally important is the issue of student privacy," Webster said.
"If the school is considering installing CCTV in bathroom and toileting changing areas... they absolutely must go through a really considered process of assessing the risks around that, against the safety benefits that they hope to get."
Schools needed to be open with their communities about using CCTV, have clear signs where it was used, and focus cameras away from areas where students would use toilets or get changed, he said.
They should also consider not recording audio and ensuring access to the footage was limited.
The Office of the Privacy Commissioner recommended schools carry out a privacy impact assessment (PIA), before installing surveillance cameras.
"Doing a PIA helps people identify and assess the privacy risks of data collection, use, or handling of personal information," Webster said.
"A PIA will also propose ways to mitigate or minimise those risks.
"This would include the consideration of less privacy-intrusive means of achieving the outcomes sought."