"I'm not pleased he's resigned because he was an excellent teacher, but if the issues were found to be true ... we'd have to take action."
Police were aware of the incident, but a spokesman said because the student was 17, they could get involved only if there were specific concerns about her welfare.
The pair's relationship has been discussed widely on Facebook by Wainuiomata High students.
Facebook friends of the student said her profile lists her as having been engaged since August 11. Mr Hotter has closed his Facebook profile.
On his myspace page he talks about his two children, stating: "If you can work out the difference in age between my two kids you'll understand how complicated my life is ..."
Mr Hotter's partner would not comment. Attempts to contact Mr Hotter and the student were unsuccessful.
Mr Hotter is registered with talent company Gail Cowan Management. He has featured in many Wellington plays, including Heat, where he spent the production dressed as a penguin.
Last year, the Teachers Council deregistered four teachers for serious misconduct after inappropriate relationships with students.
- Wainuiomata News