Western Heights deputy principal Jim Gemmell travelled to Christchurch to read a letter of support at Winston Waerea's sentencing, a copy of which has been provided to The Daily Post.
In it, Mr Gemmell described Waerea, known as Wini, as an asset to the school who was regarded as a "father figure" by staff and students. He has been the school's caretaker for 11 years.
Mr Gemmell wrote: "I have never heard a bad word said against this man and I hold him in the highest regard. To me, Wini is nothing but totally dedicated, honest and trustworthy. I would doubt that Wini would ever knowingly perform a dishonest action and, having witnessed his demeanour since his guilty verdict, I continue to hold this opinion."
Mr Gemmell went on to offer supervision or "whatever is required to help this man" and said the school's board had "taken the unprecedented step of offering Wini the opportunity to stay in his school house should he be unable to continue working" although he noted Waerea would be unable to continue paying rent to the ministry if he was unable to work.
In sentencing, Judge Brian Callaghan reportedly said the nature of Waerea's offending meant he wasn't a risk to anyone at the school.
But Crown prosecutor Kathy Basire said while the Department of Corrections had approved the arrangement she wondered whether the school "really understands what position they are putting themselves in".
Board chairwoman Hali Osborne said the board had no concerns about Warea serving his sentence on school grounds and had not considered it necessary to inform parents or students.
"It was a one-off incident that had nothing to do with his ability to do his job at the school or the safety of our students," she said.
She said that among those who were aware of Waerea's conviction, the general reaction had been sadness that he had been put in a compromising situation and made a wrong choice as well as support for him to continue working.
A Ministry of Education spokeswoman said the matter was between the school's board and principal and did not respond to questions on whether the ministry had been consulted about the arrangement.
Ms Pelham also said it would be inappropriate for her to comment as the matter was being handled by the board.