The boy's age is not stated but his stepmother gave evidence that the man worked one-on-one with the boy from 2013 to 2015, and that the boy's attitude to life changed towards the end of 2013.
"He got upset easily and was angry and would not express what was going on for him," she said.
"At the end of 2015 [the boy] kept running away from home. He was sent to Australia towards the end of 2015 after he had left school.
"After [the boy] had left for Australia, the respondent repeatedly rang [the stepmother's] cell phone asking for [the boy]. When [the stepmother] asked why the respondent was ringing, the respondent advised that her was offering [the boy] a job.
"[The boy] returned to Auckland on February 28, 2016. When the respondent rang a few days later, [the boy] spoke to the respondent but put the cellphone on speakerphone so that [his stepmother] could hear the conversation.
"[His stepmother] heard the respondent say to [the boy], 'I miss you so much,' and, 'I really want to see you.'"
Later the man said, "I want to be alone with you," and, "I'll pick you up."
The stepmother then took the phone and told the man: "You are disgusting and I'm going to ring the police. Don't ring again."
The man hung up.
The boy then told the school principal that the man "would sit close to me when I was reading and keep moving closer to me".
"He put his arm around my shoulder. We read the book together. He rubbed my neck," the boy told the principal.
"The next lesson I sat opposite him at the table and he told me to come round and sit beside him. He started touching my leg (upper thigh). I said nothing. I felt sick as I'm not gay.
"One time he told me he is gay and has a boyfriend since his wife passed away. When I told him I had a girlfriend, he told me what to do, kissing and sexual act stuff."
The man denied telling the boy that he was gay or had a boyfriend, talking to the boy about the boy's girlfriend and touching the boy in the way the boy alleged, "but accepts that at times he would pat [the boy] on the arm, back and shoulder".
He admitted that he rang the boy's home on a number of occasions, spoke with the boy on one occasion and "made a number of inappropriate comments to [the boy] during the conversation, including stating that he wanted to be alone with [the boy] and missing [the boy] and wanted to see him again".
The tribunal said previous cases had established that "there are situations in which adults with sexual motives start with more subtle measures to test the waters and start to cross the line of a teacher/student relationship".
"The fact that this type of conduct can be a tactic in sexual grooming is one of the reasons it is not tolerated."
