The Education Council is investigating an alleged incident at Ngaruawahia High School involving a teacher and student.
Fairfax reported that a teacher who caught a student smoking on school grounds allegedly stubbed the cigarette out on her hand.
The teacher has since resigned, Fairfax said.
An Education Council spokeswoman confirmed the organisation is "talking with the school about an incident" after recently becoming aware of the issue.
She said the council's complaints assessment committee investigates allegations and makes recommendations about whether to take the case to a Disciplinary Tribunal.
At worst the teacher could lose their registration.