An Auckland teacher has been deregistered after hitting a Down Syndrome boy with a toy lizard.

Cristina Batang admitted using the plastic lizard to hit an 8-year-old boy with Down Syndrome who was trying to pull the pants off another boy with the same condition at Mt Richmond Special School in Ōtāhuhu in August 2017.

She also admitted that she "regularly pulled the hair of children in her class" in 2016 and once pulled a student's ear.

The Teachers Disciplinary Tribunal has found that her actions amounted to "physical abuse" and has cancelled her teaching registration.

"We seriously question the respondent's suitability for the role of a teacher," it said.

"The respondent's treatment of students was completely unacceptable, only made worse by the vulnerable nature of these young people."

Batang, who was a relief teacher at the school for what principal Kathy Dooley described as "quite a few years", provided medical evidence that she had suffered a stroke in November 2015 which limited her movements and caused ongoing shoulder pain.

She told an Education Council investigator last April that the hair-pulling and ear-pulling incidents "might have happened when [she was] having the signs and symptoms of stroke".

"The respondent stated that she sometimes had held the students' ears as a reminder to listen," the tribunal said.

"The respondent also commented that 'kids know who they can manipulate', and that 'in my heart, I want this [sic] kids to be productive and be a part of the community where the members have expectations of each other.

"In my mind, train the child in the way he should go and when he is old he will not depart from it," Batang said.

She told the investigator that she used the plastic lizard to hit the 8-year-old boy on the back because the boy was "pulling down the trousers of [the other boy] who [was] half lying down on sofa".

"I tried to separate [the boy] from [the other boy] while telling him it is not a funny game," she said.

"While still holding the toy in the tail, I was taking [the first boy]'s hand off the trousers of [the second boy] and told [the first boy] to go."

Batang resigned from her job after the school investigated the lizard incident and later advised that she did not intend to renew her teaching certificate for health reasons.

The tribunal found that the combination of all the incidents justified cancelling her registration.

"The hitting with a plastic toy might not warrant cancellation, but the repeated pulling of hair..., the pulling of a student's ear, alongside the incident with a toy, take this offending into a much more serious class," the tribunal said.

"It is difficult for us to see how any penalty short of cancellation would meet the protective purpose of disciplinary proceedings."

However in a separate case, the tribunal allowed former Onehunga High School teacher Gabriel Emilio Hughes to continue teaching despite swearing at students, giving them "verbal put downs", punching a wall and banging his head against a classroom wall in frustration.

"On a number of occasions the respondent swore at students in his Year 13 class and/or in the presence of students in his class, saying things like 'f***' and calling students 'f***ing useless'," the tribunal said.

The tribunal accepted that Hughes was a new teacher who was still only provisionally registered, and noted that he had expressed remorse and undergone therapy with a psychologist.

It censured him and ordered him to complete appropriate professional development and undergo mentoring for a year after he resumes teaching.