A teacher who had an inappropriate relationship with a Year 13 student and suggested they enter into a threesome with another boy has been ordered to pay more than $6000 in costs to the Teachers' Council.

The teacher, whose name is suppressed, was censured for professional misconduct earlier this year by the New Zealand Teacher's Disciplinary Tribunal for her behaviour.

The tribunal found the teacher - who had recently split from her husband - had invited the Year 13 student to live with her knowing he was a pupil at the school where she taught. As well as suggesting a threesome with him and another boy while in her bedroom, the teacher also had a photo of herself and her husband engaged in a sex act that the boys saw.

A costs decision from the tribunal, published today, ordered the teacher to pay $6266.51 towards the case costs of the Teachers Council Complaints Assessment Committee, which brought the charges against her.