Violent, disruptive or misbehaving pupils were suspended, stood down or kicked out of school more than 27,000 times last year, with 14-year-olds the worst culprits.
Teachers say the figures reflect growing behavioural problems and violence. Many feel under threat of physical attack.
The most common offences were continued disobedience, assaulting other pupils, verbally abusing teachers or drug-related misconduct.
Examples included pupils selling drugs to classmates on school grounds, use of weapons in unprovoked attacks on pupils, bullying and assaults on staff.
Boys were more than twice as likely to be disciplined as girls, Maori pupils had much higher misconduct rates than non-Maori and 14 year-olds offended the most.
Minister Chris Carter will issue the Education Ministry's annual student engagement report today. It shows pupils were permanently or temporarily removed from class 27,200 times during 2007.
Most cases were one-off incidents, with offenders stood down for a few days before returning to class.
More than 1600 pupils were removed from school for serious misconduct, though most were under the legal school-leaving age of 16 so had to be enrolled at another school or alternative education provider.
But overall numbers fell by nearly 2000 compared with a year earlier, suspensions hit an eight-year low and early-leaving exemptions for 15-year-olds halved.
Mr Carter hailed the drop as evidence schools were using more resources to deal with badly behaved kids, keeping them engaged at school longer and "reducing the levels of unacceptable student behaviour".
However, teachers and principals reject suggestions behaviour has improved, saying schools are under pressure to cut suspension rates, even though staff often face violence and abuse.
Secondary Principals Association president Peter Gall said schools regularly had to balance the rights of individual children to an education with the safety of fellow pupils and staff.
Fighting, drugs and disruption were constant problems. He did not believe unacceptable behaviour had reduced. "Anecdotally, I wouldn't say that's the case."
Post Primary Teachers Association president Robin Duff said schools were under pressure from the ministry to rein in suspensions and exclusions. But many teachers faced daily abuse and disobedience.
"We certainly continue to hear of incidents where other students or staff feel they're in very threatening situations."
Educational Institute president Frances Nelson said 27,200 children being removed from school for behavioural issues was a sad statistic.
"That's still a huge number of students that have been excluded. It points to a significant problem."
- The Dominion Post
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