Allegations involving a Marlborough Boys' College staff member have been referred to police and Oranga Tamariki, the office of the Minister of Education says.
The school said in a statement it is working through a sensitive matter relating to a staff member who was now on leave, and also possibly a student.
Board chair Sturrock Saunders said it was not appropriate to comment further, except to say that the matter has been referred to Oranga Tamariki and police were investigating.
Police would not say whether "specific individuals or organisations are, or have been, under police investigation".
Mr Saunders said the college was liaising with New Zealand School Trustees Association and the Ministry of Education to make sure the matter was being handled in line with best practice.
He said the school was taking care to protect its students, and asked media to be "very circumspect around reporting on this matter", particularly as the matter might relate to a student and would therefore would be subject to significant privacy considerations.
"We can confirm that our school is working through a matter relating to a staff member.
"The staff member concerned is on leave while the matter is worked through.
"I trust that this provides you with an assurance that we take all matters seriously and seek advice to ensure that we handle matters well," Mr Saunders said.