Education and Training Act 2020, s 34
No, this is not acceptable. Students who have special educational needs (because of a disability or another reason) have the same rights as other students.
You should seek help from the Ministry of Education’s Learning Support services to make sure your child is appropriately provided for. You can also contact the Office of the Children’s Commissioner, which can help with information and advocacy.
It’s against the law to limit the amount of time your child can go to school, unless you and the school agree on a well-being transitional plan. See “Exemptions from having to go to school”