Mt Albert Grammar School has been accused of going "overboard" in its war on drugs by getting sniffer dogs to search the school.
Headmaster Patrick Drumm said he called in NZ Detector Dogs to search the school last Thursday to ensure "the best and safest possible learning environment for our young people".
He also wanted to send a message to students that drugs were not acceptable at school despite a planned referendum on legalising cannabis.
"The last thing we need is a mixed message that in some way it might be permissible or decriminalised or cleared to go into schools, which we know has a massive impact on the young brain," he said.
He said it was the third year in a row that he had ordered the search, and no drugs were found.
"It's an educational approach we take to it, it's not a punitive one," he said.
But Auckland Council Youth Advisory Panel chair Veisinia Maka, 22, said the move was "a bit overboard".
"When I was in high school, which wasn't that long ago, we never did anything like that," she said.
"I think there are many ways to get people talking about the seriousness of drugs and alcohol. That is a discussion that needs to be really open because everyone is trying to figure out how to deal with that, especially when it comes to young people.
"It's kind of like a starting point, when people are starting to have a conversation about how do we make sure this is a safe place for learning, rather than saying, 'Let's just confiscate it.' Because it obviously exists."
managing director Janet Williams said her company carried out drug searches for 80 to 100 schools nationally, but searched only school premises and not individual students.
"The Education Act says dogs can be brought into some school facilities, not students themselves," she said.
"We take the students out of the classroom before we screen them. Students are not present when we screen."
She said 99 per cent of the schools that called in sniffer dogs were acting proactively rather than responding to particular incidents.
"Most do it as a proactive measure to make sure that their schools are just like any other workplace for health and safety, that there are no drug hazards within their schools."
Education lawyer Carol Anderson said the Education Act was amended in 2014 to say that contractors "may bring a dog that is trained for the purpose of searching to a school and use the dog for the purpose of searching school property (including lockers, desks, or other receptacles provided to students for storage purposes)" - but may not search students themselves.
"Contractors can't conduct searches of students or their bags or tell students to surrender items. Only teachers or other staff authorised by the board can do this," she said.
"Teachers can require a student to produce or surrender an item they reasonably believe the student has on their person or in a bag if they have reason to believe it is likely to endanger the safety of others, likely to detrimentally affect the learning environment or likely to pose an immediate threat to the physical or emotional safety of any person.
"A teacher can conduct a search of a bag or other item under the control of the student if they believe it contains an item that is likely to pose an immediate threat to the physical or emotional safety of any person.
"Searches must be conducted according to strict criteria respecting the privacy and dignity of the student."