Police were worried bypassing the finger swipe access to the laptop could wipe the hard drive, the tribunal heard.

A former teacher accused of serious misconduct refused to open his fingerprint encrypted school laptop, despite investigators saying it was the best way to dismiss allegations of inappropriate conduct with students.

The man's teaching was called into question for inappropriate conduct with boys – he received multiple warnings about letting students get too physically close, and there were reports of him favouring a certain student and adding others as Facebook friends.

The man worked in a rural Waikato school from late 2007 to early 2014, mostly with seven and eight-year-olds.

He also had IT responsibilities.

He has not been teaching since about March 2014 but appeared before the NZ Teachers' Disciplinary Tribunal at Seddon Park in Hamilton.

The majority of concerns about his behaviour were from 2010 to early 2014, and included observations of a student stroking the teacher's hair and one resting his legs on the teacher's legs.

One parent felt their child had developed a "sense of entitlement" after being treated as a teacher favourite.

The teacher had received formal warnings, support and been through mediation before the tribunal.

The school laptop was meant to be part of the investigation but even police could not get into it using the password provided, Complaints Assessment Committee counsel Gaeline Phipps said.

Encryption was high so there were worries that trying to bypass the fingerprint access could wipe the hard drive.

The teacher refused Phipps' requests to provide his fingerprint at the hearing, which she said could mean he was hiding something highly objectionable.

The teacher, who represented himself, said he had swapped to using the password as it was more reliable, and he didn't know how to respond to Phipps' inference.

"I've given the password over," he said. "I'm not touching the laptop."

Phipps asked him what he was afraid of and the teacher said he was worried about bank account and credit card details, family photos and files which could have been transferred when he used the laptop to fix other people's computers.

The refusal disappointed tribunal member Susan Ngarimu, who said there had been veiled innuendo about grooming in some of the cross examination.

"You won't take one simple step to swipe your finger mark to remove all of that innuendo," she said.

"I'm just wondering why ... if you want to remain in the profession."

The man's former principal said he had been seen as a cool teacher by kids but there had been multiple issues.

"There were concerns that he was being a mate, not a teacher."

He didn't seem to recognise the boundary issues so the principal said he had started making regular, unannounced visits to the man's classroom from 2010.

On some occasions, students close to and touching the teacher moved away when they saw the principal enter, the principal said in evidence.

He'd seen a student lying on the floor with his feet up on the teacher, who was seated on a chair, and also a student touching the teacher's head and gently pulling his neck hair.

"It was almost like a caress ... but with a finger and thumb," the principal said.

But the teacher said warnings from the school had put him on edge.

"At absolutely no stage during my teaching career did I mean any harm to any student," he said.

"I was petrified of any kid touching me at that stage."

He had not initiated physical contact, and had not noticed the hair stroking, he said.

A parent complaint about their child's behaviour changing as a result of being treated favourably by the teacher had "blindsided" him, as he had just been trying to build the boy's self-confidence.

Another problem was a spam sexual email which a student saw on the teacher's screen, prompting a parent complaint in February 2014.

The teacher said his junk email had been open and the email had automatically appeared on screen.

He'd discussed internet safety with the student concerned but acknowledged he should have reported the incident.

The teacher left the school later in February, after a conversation when he was told his laptop would be looked at and searched for any deleted photos which contained skin.

He described feeling like "a cold bolt of lightening going down my spine" when he was walking into the office for that conversation.

The tribunal was told he made a suicide attempt that night but said in evidence that was not directly related, and he'd recently changed to medication that had been incorrectly prescribed.

The disciplinary tribunal said it would release its decision as soon as possible.