There are fears a law change governing how teachers can search students for items such as drugs and weapons will create a potential minefield for schools.
Changes to the Education Act come into force on January 1 and will change the rules around searching students but there is no provision for allowing for a search for stolen property.
The Ministry of Education is working with teacher groups and experienced principals to prepare guidelines so boards, principals, teachers, and staff members can understand what their powers and obligations are.
But New Zealand Principals' Federation president Philip Harding said the law change would unintentionally create potential problems for schools and he gave an example.
"If an item has gone missing in a classroom, say a chisel from a technology class, and the loss is suddenly spotted at the end of a lesson, we can't say to the group of students 'show me what's in your bag'.
"You can't prove you reasonably suspect each and every one of those people stole that chisel."
Mr Harding said he had heard concerns teachers would have to choose to break the law for the health and safety of their students and colleagues.
Te Puke High School principal Alan Liddle is a member of the sector reference group working with the ministry and said his group's job was to go through the proposed guidelines, critique them, and come up with some scenarios.
Mr Liddle said there was a lot more work to be done before the guidelines could be released.
Otumoetai College principal Dave Randell said if there was need to search a student's bag, the person was invited to open the bag and 99 per cent of the time the student would comply.
He did not think the way the school dealt with these situations would change with the law change, but said he would know more when the guidelines were released.
NZEI immediate past president Ian Leckie, also principal of Tahatai Coast School, said if a situation ever arose where a student's belongings needed to be searched, the parents were always involved.
Ministry of Education sector capability and support Katrina Casey said the ministry was working towards having the guidelines published by the end of the year to coincide with the January 1 law change.