New figures show the rate at which schools are suspending, standing down, excluding and expelling their students is the lowest in 12 years.
Ministry of Education statistics show schools temporarily stood down 13,700 children last year and suspended nearly 3500 - some of them more than once.
Radio New Zealand's education correspondent says that means they are suspending 5.2 children in every thousand, compared with nearly eight in every thousand 12 years ago.
Nearly half of the children stood down or suspended were subsequently told to leave their school.
If under 16, they were excluded and the school had to find them another school to attend. If 16 or over, they were expelled.
Continual disobedience, assaults on other students, drug use, and verbal abuse of staff were the main reasons schools punished students last year.
Principal Youth Court Judge Andrew Becroft said on Saturday that school boards of trustees are sometimes too ready to exclude problem students, which only shifts their behaviour into the wider community.