Teachers who fail to adapt their teaching for children with learning and behaviour problems need to be held to account, parents and education experts say.
They say a special education code of practice would help ensure teachers act in the best interests of children with additional learning needs.
People who work with children with special needs told RNZ some teachers and schools failed to use strategies recommended for working with children with behaviour or learning difficulties.
They said some teachers did not have the right training or support, but in other cases teachers simply did not want to change their approach.
One told RNZ he was "gobsmacked" that teachers knew they had children with behaviour problems in their classes, but did not adjust their teaching style to accommodate them.
Parents told similar stories.
One woman said her school failed to follow through on an agreed approach to working with her daughter.
"When the psychologist came in we were able to put our head together and get some really good strategies and approaches and these were not applied this year."
Another told RNZ her son had transformed after moving schools and the only real difference was the attitude of the teachers.
"Sometimes the Individual Education Plan is only implemented by the specialists and not the teacher or teacher aide working with the child. So only some team members are implementing it, not all, which defeats the purpose of it," another said.
An organiser from an online support group for families of children with special needs, Frian Wadia, said many families struggled to get specialist help for their child and when they did get it, teachers did not always do what they were asked to do.
"Quite often, yes, there is this negative attitude of 'why should we adapt things for this child', so quite often the suggestions don't get taken on board by the teacher," she said.
"It gets to the point where the child then struggles and then there's behaviour issues and things like that, so it's a huge problem for a lot of our families."
Ms Wadia said sometimes teachers did not have the resources or training to do what was asked of them, but in other cases teachers refused to change their approach.
"There's just this negative attitude of 'this is not how we do things'," she said.
Code of practice needed
Ms Wadia said families generally did not complain because they did not want to spoil their relationship with their child's school, but a code of practice would help ensure teachers acted on the advice of specialists.
"If the code ... actually had clauses around plans being upheld or specialist input being acknowledged or implemented within the classroom setting, within the school setting, then we would actually be able to do something about it."
However, Ms Wadia said a code would only work if there were also wider changes to the special education system, including law changes to give children the right to an inclusive education.
Dyslexia Foundation managing trustee Esther Whitehead said some schools did a good job because they had an effective special education needs coordinator but it was not consistent across the school system.
"Having a code of practice would essentially allow for a framework where it is more explicit and there are some KPIs to actually be addressed by the mainstream teacher," she said.
Legal help group Youth Law general manager Jennifer Braithwaite said too often students end up excluded or expelled from school because they had not received enough support.
She said the government should guarantee children's right to an education that was adapted to their needs.
"There needs to be legislative change so there is an enforceable right to inclusive education and reasonable accommodations. It's not a question of having the same, it's a question of having tailored support that meets a child or young person's needs."
Children's Commissioner Andrew Becroft said New Zealand had been slow to grasp the extent of learning and behavioural issues.
He said he often heard that schools were not meeting the needs of children with learning or behaviour problems because the problems had not been diagnosed, the school could not get the right help, or because some schools were not keen to provide that support.
Judge Becroft said a code of practice should not be introduced until the government's learning support action plan was rolled out.
He said it would provide more support for children with additional learning and behaviour needs.
"It's based on much better early identification, on more teacher training, so that's the starting point," he said.