The numbers of students being caught for drug offences are rising. Schools say this is a good thing, as it proves their harder line on drugs is working.
Hundreds more students are being caught with drugs in high schools each year, official figures show.
A principal at one Auckland college, where 116 students have been stood down for drugs in two-and-a-half years, said his students could buy joints for just $5.
Principals say enhanced detection efforts are the main reason for increasing numbers of students being caught with drugs. Some high schools regularly bring in drug dogs.
In the first five months of the year, nearly 1000 students were expelled, suspended, excluded or stood down, an Official Information Act request revealed, though the Education Ministry said the numbers were not yet finalised.
In the two previous full years, the numbers increased from 2441 to 2690.
Papakura High School had the highest number of stand-downs over the past two-and-a-half years.
Principal Peter Heron said the high numbers of students being caught with drugs showed strict enforcement strategies were working at the school, although students could buy marijuana joints for as little as $5 in the area.
He said: "The big thing for us is to keep the drugs out of school. I think the high number is because we are effective at catching them."
Teachers were trained to spot drug-influenced students, who were sent to nurses for blood tests. Heron said the school would "act strongly to bring families in when drugs are involved and set in place rehabilitation".
"For example, if a girl brought in marijuana and shared it with several friends, we would stand them all down."
Auckland Grammar headmaster John Morris said one boy had been excluded from the school for possession and use of marijuana before going to another school's social.
Four other boys were stood down for being accomplices.
Morris said the school had a "zero tolerance" policy for drugs and alcohol.
Social workers said there were huge differences between different school's drug policies. Robert Steenhuisen, Community Alcohol and Drug Services regional manager, said there would be expectations at Auckland Grammar among a "very powerful group of parents" that the school be completely drug-free.
"But if you do that in areas of high deprivation, you couldn't run a school on that basis.
"You have to try to discuss these issues with parents.
"Some schools don't really want to work with our youth team. They think the best policy they can use is to expel or exclude."
Aorere College reported a reduction in drug-related stand-downs from 52 in 2009 to 14 until the end of May. Tough detection methods like spot checks and drug dogs had increased the likelihood of students getting caught, said principal Pat Drumm. But the school preferred stand-downs to expulsions.
Drumm said: "There is no greater barrier to learning than being under the influence or having access to drugs. It's destructive."
The availability of legal highs such as Kronic, which was banned last month, had muddied the waters. "The mixed messages kids were getting was just rubbish," Drumm said. "Finally the politicians listened."
The ministry will be providing schools with guidelines for search and confiscation soon, which should help manage challenging behaviour.
Group manager of curriculum and performance, Chris Harwood, said: "Although there is an increase of 152 stand-downs due to drugs in secondary schools between 2010 and 2011, there was an approximate increase of 3000 students attending secondary schools.
"This must be taken into account when comparing across years.
"The ministry recognises schools need support to manage challenging behaviour and is investing $45 million over four years in the positive behaviour for learning programme."
TEENS PUT TEACHER IN HOT SEAT
Several teenagers have been caught smoking cannabis in a classroom at lunchtime to deliberately stink it out - a stunt known as hotboxing.
The students closed all the windows and doors so that the room retained a strong smell of cannabis when teachers returned for afternoon classes.
A parent at Mercury Bay Area School in Whitianga said several students hotboxed a classroom in the first term.
Last month, another group of students hotboxed a toilet.
Several students were stood down over the incidents.