The High Court in Wellington has ruled that schools cannot discipline foreign students for misbehaviour outside of school time.
The court has upheld an International Education Appeal Authority decision that a Tauranga school breached the Education Act by expelling three German students for smoking marijuana on their own time.
The school, Tauranga Boys College, had asked the court for a review of the authority's decision.
The college said the boys' actions broke their contracts with the school.
But the judgement by the Hon Justice Ellis said she agreed with the appeal authority that the Education Act prevailed over any contracts, and international students had the same rights under the act as domestic students.
She said the boys' contracts could have been terminated if their school fees had not been paid, but their expulsion could not be justified under the Education Act.
"I accept that the upshot of this analysis is that the school had no jurisdiction over international students outside of school hours."
The judgement said homestay parents and the police should deal with any problems that occurred in that time.
It upheld the Education Appeal Authority's decision that the school should revoke the expulsion of two of the boys, refund a term's fees for each of them, and refund $200 to the third boy.
A member of the Secondary Principals Association executive, Patrick Walsh, said the decision was problematic because schools were responsible for international students' pastoral care.
"Principals and the public would find it an unusual situation where an international student could drink to excess, engage in dangerous activity compromising their own safety and others, and the schools who invited them here would be powerless to stop it."
He said the decision needed urgent review and discussion and it might be necessary to amend the Education Act or the Education (Pastoral Care of International Students) Code of Practice, which governed all education institutions that enrolled foreign students.