A female teacher has resigned from a Catholic school amid allegations of inappropriate conduct with two students.

Hamilton's St John's College has confirmed it suspended the teacher after receiving complaints from two parents. The school launched an investigation but she resigned on Friday.

Principal Shane Tong said he had sent a mandatory report to the New Zealand Teachers Council, which would now carry out its own investigation.

Mr Tong would not comment on specific details but said the college, which has a roll of 760 boys in years 9 to 13, was supporting the affected students and had contacted the parents of those who had the most interaction with the teacher. An internal investigation was ongoing.