Students with special education needs are "grossly over-represented" among students who are being informally removed from schools, a new report by YouthLaw Aotearoa says.
It says families are often informally persuaded to take their child from a school and it is not reflected in formal statistics.
Education Minister Hekia Parata said in August that student stand-downs, suspensions and exclusions were are their lowest level in 16 years.
But Jen Walsh, a solicitor and author of the report, said that did not paint the real picture.
She says there has been a dramatic rise in the caseload related to informal removals since 2013.
Appeals tribunal recommended
The findings are based on YouthLaw's own case work and a national survey which elicited 53 responses.
A lot of its case work is with students with autism or ADHD.
The report is not claiming to be quantitative and Walsh says better research is needed to monitor informal removals.
The report recommends the establishment of an appeals tribunal similar to one in Britain that has the power to direct schools to reinstate students or direct them to take different measures.
The report also recommends better guidance for schools to ensure that students with special educational needs are reasonably accommodated in mainstream schools.
Walsh said schools were "culturally incentivised to perform."
"Students who don't easily fit within that norm become difficult to manage within that performance structure and it can mean they are subject sometimes to additional disciplinary processes or informal processes."
'The forgotten students'
Allan Vester, the chairman of the Secondary Principals' Council, said he would not be surprised if there had been an increase in the number of students informally removed with special education needs.
"Schools really, really struggle to manage those students," he said.
"What is sometimes forgotten in the debate is certainly the students with special needs should be looked after but when a school is not funded to look after them adequately, then there is a real tax on education for every other student.
"Everyone else's education in the class is diminished to some extent if the teacher has not got extra support for that student with needs and they spend a lot of their time dealing with that student."
YouthLaw was an advocate for the individual student.
"Whereas the schools are often making the judgement 'if we keep this student here, this is the effect it is going to have on every other student we've got.'"
He believed the Ministry of Education was well aware of the issue. It was really an issue of funding.
Additional support for schools was needed.
Rights of children to a local school
Up to 50,000 students a year are directly supported through special education grants which was $37 million in the year ended June 2014, and was part of $586 million spent by the Government that year on additional learning support for up to 100,000 students.
Ministry of Education deputy secretary Kim Shannon said every child had the right, under New Zealand law, to attend their local school if they choose to do so.
Students could only be removed from school or kura for behavioural reasons when the school followed the correct process as set out in the Education Act.
"Schools sometimes face extremely challenging behaviour from a very small number of children and young people," she said.
"When they take action it is almost always in the interests of the safety of other children, teachers and the child whose behaviour is a concern.
'If a school suspends, excludes or expels a child usually it is only done after a number of other things have been tried - and in by far the majority of cases very sound processes are followed.
'Small minority get it wrong'
"We are however aware that in a very small minority of cases some schools have not followed the correct processes. We do not condone these practices and where this is drawn to our attention we will act to ensure the proper process is followed."
If any parent who was concerned their child had not been suspended or excluded correctly, the ministry would take up the matter with the school concerned.
A five-year-old girl from South Auckland - D
D had been diagnosed with ADHD and anxiety, resulting in violent and defiant behaviour at school. The school told D's parent that she could not attend full days at school, and insisted that her mother pick her up early on three days which she was permitted at school per week. At times when D's behaviour escalated due to lack of support, D's mother was advised that D remain away from school for a period until the school felt she could return again. No formal disciplinary steps were taken and D was removed from school for substantial periods of time. Eventually D's parents felt that she was so unwelcome at school that she was withdrawn and an application was made to home-school her.
A 13-year-old boy from West Auckland - S
S had been diagnosed with ADHD and had been acting out at school. Following discussions with school management, S's parents felt that they had no choice but to agree to the school's suggestion that S only attend part days and part weeks at school as the school was having difficulty sourcing and funding additional special educational support for him. S's defiant behaviour continued and escalated due to lack of support. S's parents were called to a meeting with school management. They were advised it would be better for S if he was to stay away from school for "a while" and perhaps when his behaviour was more manageable, he might be able to return or transition to alternative education. It said if S did not stay away, he would be subject to a formal exclusion process and have a bad record. He stayed away for almost a year before seeking advice from YouthLaw.
A 15-year-old boy from Wellington - A
A had been tardy and had not completed his homework on a number of occasions. He was then told he was to be internally suspended, excluded from particular classes and made to sit elsewhere. Following the internal exclusion, the school phoned A's parents and advised it was best for A to stay home as he had been making inappropriate comments in class. In subsequent meetings with the school, A's parents were pressured into moving him to another school. The school said A's misdemeanors were not serious enough to warrant suspension but they would take such action if his behaviour continued.
A 13-year- old boy from Hawkes Bay - E
E was diagnosed with Asperger's syndrome. E suffered many disciplinary actions and his parents felt he was not given disability support. In 2014, he was involved in a fight involving a large crowd of students, but he was the only student that was stood down and suspended by the school. In 2015, E was again accused of assaulting a student in a situation where he had no intention to harm and his disability had not been supported. The Board of Trustees simply affirmed the principal's allegations that E was prone to behavioural issues as opposed to living with a disability.