Schools are increasingly using illegal suspensions to remove trouble-making students from the classroom, according to anecdotal evidence.
While overall formal suspension numbers have dropped, YouthLaw has reported 'Kiwi suspensions' - informal removals that don't meet legal requirements - are growing.
"Although most schools are engaging in best practice procedures, the current regulatory frameworks permit variable and inconsistent approaches to school discipline from school to school," solicitor and report author Jennifer Walsh says.
"In some cases this can result in students being deprived of access and participation in education on the basis of erroneous or misguided ideas."
The anecdotal evidence comes from 53 survey respondents between November 2015 and August this year.
Special needs students are "grossly over-represented" in both formal and informal removal statistics, the report concluded.
The Government's education select committee is currently investigating the support available for students with dyslexic, dyspraxic, and autism spectrum disorders.
YouthLaw has called for greater guidance for schools carrying out disciplinary practices, as well as greater oversight through an Education Commissioner or independent tribunal.
The Green Party has backed the latter and called for an independent tribunal established.
"These kids need to be in school; turfing them out is not the answer," education spokeswoman Catherine Delahunty said.
"An independent tribunal that determines whether a child has been unfairly excluded from school would give parents somewhere to turn when the system tells them that they're out of options."