"There's a number of kids that are experiencing various levels of anxiety, irritability, restlessness, feeling sad or down, tired, groggy, headaches, that kind of stuff," he said.
Dr Brown said it was not uncommon for the students to use vape liquid containing 60mg of nicotine, compared to a single cigarette, which contained 10-to-20 mg of nicotine.
"It's so easy for them to do. They can be sitting in class, they can be vaping, no-one would know."
Dr Brown said the R18 restriction on nicotine vape liquid did not seem to pose any barrier to teenagers obtaining it, either from friends and relatives, or directly from retailers, and schools needed to accept that would happen and focus treating the addiction.
He said the teenagers had never smoked and had not taken up vaping for the novelty of blowing clouds of smoke.
"It's quite a common experience here at this school, and I would say similar to other schools from what I've read around this, that the kids who are getting up there in high nicotine levels are definitely finding it troublesome," he said.
"They come to us and they want some kind of guidance, help and some kind of supportive effort to get them off of this addiction that they're facing."
Dr Brown said the school was developing a therapeutic model for helping teenagers quit nicotine addiction.
Ben Youdan from the anti-smoking group ASH said principals had legitimate concerns about vaping and it seemed to be more of a problem in schools in higher-income communities, while smoking was still a problem for schools in poorer communities.
"We know a lot of students are trying it, we know at least a third of Year 10s and probably slightly more when you get to the older kids have tried a vape, they've tried a friend's, they've experimented with it," he said.
Mr Youdan said surveys showed regular vape use among young people was at only one or two percent, but he agreed that vape use could be increasing and that was why there was a lot of urgency around managing the marketing of vaping.
However, he said vaping had helped tens of thousands of people to stop smoking.
"Vaping absolutely has a place but we've got to get the balance right between protecting kids and encouraging and supporting adult smokers to make the switch," he said.
Vaping facts:
• The New Zealand government is preparing to introduce a bill on vape regulation, which would limit vape flavours to tobacco, menthol and mint.
• And Auckland secondary school principals are backing the government's plan to ban most vape flavours, saying vaping is reaching epidemic levels among their students.
• But an American study that came out on 17 September (NZT) found users of mint and menthol e-cigarettes are exposed to high levels of the carcinogen pulegone.
US health officials are investigating deaths possibly linked to vaping.
• A study done in NZ showed that smokers who combine vaping with nicotine patches are nearly twice as likely to quit as those using other cessation methods.
• And earlier this year Associate Minister of Health Jenny Salesa said vaping could be the breakthrough to reduce high smoking rates for young Māori women.
• A website that provides information and advice on vaping in New Zealand was launched in June.
