In October 2014 he suffered a head injury during a rugby game, which led to post-trauma migraines, fatigue and problems with concentration. He reported being irritable, angry and sensitive to noise, the decision said.
He returned to work in December that year, earlier than recommended by his doctor.
In February 2015, he "became unhappy with the behaviour of an 11-year-old boy" during a kapa haka class. The boy was ignoring his directions and was unwilling to participate in the practice.
"In front of the rest of the class, the [teacher] instructed the student that, because the student had been disrespectful, the student must 'hongi the wall until respect is given to the mauri of the Rauma kapa haka and to all the taina and their mauri that he had whakaiti [disrespected]'," the decision stated.
"The [teacher] took hold of the student's head with one hand and moved the student to the wall. He turned the student's head so that his nose was against the wall. He pushed the student's face into the wall, but not with such force as to hurt the student."
He then told the boy and the class "this is what happens if you do not respect the kapa haka room".
When the boy tried to turn his head away from the wall, Rangihau "physically cradled the student's head with one hand and turned his face back to the wall".
"Other students in class were laughing. The student started crying."
Despite another staff member entering the room to take away two students, nothing was said, and the boy remained against the wall while Rangihau continued to teach the class. He was only allowed to move away from the wall when the teacher asked: "kau tau to mauri?' and he replied, "yes".
Rangihau was confronted about his behaviour the next day, and admitted what happened, but said he had not assaulted the boy and had not intended to cause him harm. On reflection, he said he should have removed the boy from class, but there was no other supervising staff available.
He told the disciplinary tribunal he was still suffering headaches and stress from his head injury at the time, and that a breakdown in relationship with the school principal - who he said seemed displeased at him taking time off work to recover - had added additional stress.
Rangihau later apologised to the boy for belittling his mana. But said he had been using the 'hongi the wall' technique in his class for a while, and none of his mentors or the principal had expressed concern.
He described it as "like sitting in the naughty corner with your face to the wall, but in a Maori context".
However, it was a last resort punishment, he said, describing it as "quite extreme".
Rangihau was described by supporters as a "loving father, supportive husband, and an excellent Maori male role model in the community", who had been hired for his fluency in te reo Maori and Maori values.
The disciplinary tribunal accepted he was still suffering the effect of a concussion, but said he had a "somewhat worrying lack of appreciation of the boundaries between physical contact for acceptable incidental guidance, and the use of force for correction".
"The tribunal further finds that the respondent's grasp of the concept of assault was at the time of this hearing at best vague and inaccurate."
It was concerned he was using his head injury and relationship breakdown with the school principal as a "scapegoat" for his behaviour.
While he had used "relatively mild force", it had still caused distress to the child on the day, the tribunal said. It was sustained, and represented the use of force for correction and punishment.
This amounted to serious misconduct, it ruled. However, he had "significant gifts and talents, and can make a significant contribution to his community". Instead of cancelling his registration or formally censuring him, it ordered Rangihau to complete a professional development course, in particular with instruction on classroom management techniques.
He was also ordered to inform any new employer of the disciplinary decision for the next two years, and to get written acknowledgement that he had done so.
Rangihau was censured on appeal.
