Neal was at a dinner held for some of the school's students, when one student invited him to be in a photo with her. While posing for the photo, Neal placed his arm around the girl and touched or pinched her bottom.
He then told the student she had a "nice bum".
Neal later admitted the allegations to Onslow's principal, but said the behaviour was completely out of character.
"The only change in my normal behaviours is to have begun medication for depression. I have been taking a drug called Fluoxetine every evening. I have looked this up and discovered it is an alternate name for the better known Prozac. It seems that a common side effect is behaviour change. I did not know of this side effect.
"I took this drug at about 7pm and had not eaten since lunch. This is the only factor I can suggest as a reason for my appalling behaviour. I am completely ashamed of myself."
In its September 13 decision, the tribunal said touching and pinching a student's bottom in a sexual manner and making a sexual comment about the student raised significant questions about Neal's fitness to teach, particularly whether he could maintain professional boundaries.
The tribunal heard that Neal was on two medications whose effects couldn't be established, but confusion was a possible side effect of both.
He had since changed his medication and believed a repeat of the behaviour was very unlikely.
However the tribunal found that although Neal's medications provided some context for his actions, they were not a defence.
Neal told the tribunal's Complaints Assessment Committee - which carried out the initial investigation - that he felt awful about his behaviour and accepted it was unprofessional.
But he also said the student was being "sexy" and "lovely" at the time and that she "threw herself at him" by putting her arm around him and pulling him in.
The committee and tribunal agreed that those comments showed he did not take full responsibility for his actions. They were "inconsistent with his explanation that the conduct was a side-effect of medication he was taking and was out of character".
The committee also argued his actions demonstrated "a clear lack of insight into the power imbalance between students and teachers and the responsibility of the teacher to maintain professional boundaries at all times without exception".
Neal had been teaching for nearly three decades, covering English, media studies and coordinating outdoor education. During that time - much of it in a leadership position - there was no history of other concerns being raised, his representative said.
Neal had handed in his resignation before the incident and planned to leave at the end of that year. However he could still teach, including relief teaching roles, as his license would not expire until next year.
The committee suggested the most appropriate action would be to cancel Neal's practising certificate and put conditions on him applying for a future certificate.
However the tribunal found that although his actions amounted to serious misconduct and could not be tolerated in the profession, cancellation of his certificate would be too severe a penalty for the level of his offending.
Neal was censured and required to seek mentoring around professional boundaries and provide a reflective statement showing he understood and would stick to those boundaries.
He retained his practising certificate but was required to tell all employers of the decision for the next two years - including any schools where he did relief teaching.
