Secondary school pupils were also on the bus.
The Otago Daily Times interviewed the parents of two children who saw the incident but has chosen not to name them or identify the bus route involved, to protect the children who were on board.
The mother said her 9-year-old and 5-year-old children had reported what happened to her.
"We put our children into the safe care of this school bus.
"Never would you think anything [like this] would happen on a school bus."
The community rallied and further details of the incident quickly spread.
"I guess that's a positive out of it — we realised we're a tight-knit community, we don't necessarily know each other well but when something happened we made sure like the tom-tom drums beating that all the children were fine and felt supported."
She said one mother had questioned the bus driver and another, the mother of the boy who was allegedly grabbed by the neck, had stepped on to the bus to ask what had happened.
"She sent her boys away first, so I thought she was quite courageous."
She had contacted Go Bus and not had a response.
"I found it incredibly difficult to get a contact number for them.
"I used their contact forum and said there was a, in my opinion, serious bus incident and I wanted to be called immediately."
She further specified she did not want her children on the bus if that driver was going to be at the wheel.
"I've never been contacted."
She said the feeling among parents was the children had dealt with it well.
"What they did was sheer out of fear, they sat down and were quiet but I am surprised none of the college kids spoke up."
Her husband expressed some disappointment with how the situation was handled at school level, where the children's account of events was called into question.
The principal had said the choke hold had never happened, but the driver instead had grabbed the boy by the shirt.
"Irrespective, he's still assaulted them [both boys] ... they're little kids, the youngest kids in school, they're at that age where [they] start to question 'nobody believes me'."
His wife said their daughter was upset by this.
However, the principal did act immediately, she said.
"She informed us she asked Go Bus to stand the driver down, and he wouldn't be on that school route again, which put everybody's mind at ease at that point."
Go Bus South Island area manager Ben Barlow said the company was aware of the incident.
He confirmed the bus driver was no longer in the company's employment.
Police confirmed they had received a report of an alleged assault that occurred last month and were making inquiries to establish the circumstances of the incident.