The Teachers Council struck off a teacher for showing pornography to students but failed to alert the police and the man went on to sexually abuse a boy in his community.
Victor Charles Jacka, 54, appeared at the Waitakere District Court today after earlier admitting several charges, including sexual conduct with a child.
He has been jailed for two years and seven months.
Jacka's offending began while he worked as a primary school teacher. A year after starting his job in West Auckland, several parents complained about Jacka approaching their children outside of school hours.
Jacka had organised trips, including tramps and trips to an Auckland Blues game at Eden Park.
At least some of the parents believed the school was involved in the trips but it emerged Jacka was acting on his own.
The Teachers Council, which has since been replaced by the Education Council, investigated and found he had been showing pornography to boys aged between seven and 10. Jacka was censured and was struck off.
But the organisation failed to inform the police or Child Youth and Family, so Jacka was not investigated.
According to court documents released to Radio New Zealand, Jacka went on to abuse a boy in his community.
He took the boy to Devonport and Armour Bay, near Huia.
On these outings, Jacka inappropriately touched the boy and had sexual conversations with him. He also showed him more pornography.
His offending came to light when the boy complained to his mother.
When police raided Jacka's West Auckland home, where he lived alone with his elderly mother, they found his laptop, USB drives and photo albums containing pictures of children being sexually exploited.
The police also asked the court for an order to destroy the devices.
Judge rejects home detention
A sentence of home detention was floated in court this afternoon but Crown prosecutor Jo Murdoch said home detention would be an inappropriate sentence.
She said, as well as the sexual offending, Jacka sexually groomed the children.
Ms Murdoch also pointed to remarks by Jacka to a probation officer in which he claimed some of the touching was by mistake. Ms Murdoch said that showed a lack of insight into the offending.
Judge Jonathan Down agreed.
He started with a three year prison sentence but gave Jacka a 25 percent discount for his early guilty plea.
However, the judge said the end sentence was not close to the two year cut-off required to make home detention possible.
Judge Down also spoke of the effect of the offending on the boys.
He said one of the boys felt anger and guilt. He blamed himself for the offending but Judge Down said all the blame fell on the shoulders of Jacka.
In a victim impact statement read to the court, the boy said the offending had caused him to grow up too fast. He labelled Jacka a pathetic old man.
Jacka was initially given name suppression to protect another man in the community with the same name who was not connected in any way to the offending.
Change in policy for struck-off teachers
The Teachers Council was disestablished in July last year and replaced with the new Education Council.
Education Council teacher practice manager Andrew Greig told Checkpoint with John Campbell it now published the names of all struck-off teachers.
Mr Greig said the rules for sharing information were different in 2008 and there were name suppression issues at the time.
He said the council had since developed a positive relationship with police and, if the investigation had happened today, the names would have been made public and police would have been informed.
"Our rules changed 18 months ago and we now publish the names of teachers that are before our disciplinary tribunal," he said.
"We've got much more robust, much more transparent, processes when it comes to teachers."
Mr Greig said he understood the council had a moral obligation to let other organisations know about investigations of this nature.