Racism in schools is unacceptable and reflects attitudes in wider society, groups representing teachers and principals say.
A report from the Office of the Children's Commissioner and the School Trustees Association has described what it said were disturbing and serious complaints about racist behaviour toward students in schools.
Students told researchers of problems including discrimination by teachers and abuse from other children.
Secondary Principals Association president Mike Williams said the level of racism described by the students was concerning.
"That's quite a worry and frankly unacceptable," he said. "I think as a country we do need to face up to that."
Many of the complaints were made by students in alternative education programmes, and Mr Williams said it was clear they needed a lot more support so they could succeed at school.
Educational Institute president Lynda Stuart said the allegations would be upsetting for many teachers.
"Teachers will be disappointed or upset to hear this and the reason I say that is because no teacher comes into this profession wanting to do harm to students."
Ms Stuart said schools were trying to recognise children's language, culture and identity, but not everyone was there yet.
"The education system is built on something that has been very monocultural for years," she said.
"Now's the time to change that and really look at what matters for our kids."
Post Primary Teachers Association president Jack Boyle said the report's findings would be jarring for secondary teachers, but they would not be surprised that the racism evident in wider society was present also in schools.
However, he said teachers were "ahead of the game" in terms of addressing racism and avoiding unconscious bias against their students.
Principals Federation president Whetu Cormick said the report reflected the racism that occurred elsewhere in New Zealand society.
"This doesn't surprise me, racism permeates right throughout our society and now the children are telling us," he said.
The Children's Commissioner, Judge Andrew Becroft, said students made their comments about racism without any prompting from the researchers.
"It was surprising to us, it's disturbing, I'm sure most teachers would be horrified," he said.
Judge Becroft said the report showed the government needed to listen to children as it developed education policies and goals.