Can a teacher search my child’s bag or phone?

Schools have limited search powers. The Education and Training Act 2020 and Ministry guidelines allow staff to search a student's bag or locker in some circumstances, such as where there are reasonable grounds to suspect a dangerous item or prohibited substance, and confiscate items in line with the school's policy. Searching the contents of a phone is more intrusive and raises privacy concerns under the Privacy Act 2020 and the Bill of Rights Act. Generally the school should not go through private messages or photos without a clear justification, and any concerns about criminal material should be passed on to the police. Ask the school for its search and confiscation policy and for an account of what happened, and complain to the board if it was mishandled.