The caretaker at a Napier school where a young boy was accidentally strangled on a toilet window has told a Coroner's hearing he didn't warn anyone about its defect.

Nine-year-old Aryan Banerjee died from critical head injuries in September last year.

He was strangled at Taradale Primary School, after he climbed out a toilet window when the door jammed – the handle had been taken off for repairs by the caretaker.

The caretaker told Coroner Tim Scott he didn't tell anyone that the toilet shouldn't be used.

"There was no children that I saw in the vicinity that used that toilet. I saw the opportunity to do a quick fix."

Aryan Banerjee died from critical head injuries in September last year. Photo / Supplied

Principal Marty Hantz has told the hearing he's spoken at length to the caretaker, who'd removed the door handle to repair it.

"I have told him that in the future he is to ensure that there will be adequate use of barriers, to prevent such an incident or accident occurring ever again."

Mr Hantz told the Coroner his own 9-year-old daughter got trapped in a school toilet.

"She became a little bit panicked. Banged on the door. She cried out. The teacher who was with the room next door basically came and let her out."

Aryan's teacher told the Coroner that she's changed since the death.

"I'd say I'm a lot more, not that I wasn't alert, but just with the littlest things, a lot more anxious about children."