WorkSafe New Zealand won't be taking any legal action against a Napier school where a student was strangled to death.

Nine year old Aryan Banerjee was found hanging by his clothing on a window latch handle at Taradale Primary School in May.

He tried to climb out of the toilet when the door became jammed because it was left without a door handle while being repaired.

He died in hospital three months later .

WorkSafe's chief inspector Keith Stewart said charges against the school or the caretaker are not legally justified.

"It wasn't reasonable to think the school or the worker should have planned to avoid the possibility of someone being so seriously injured climbing out of a 4th floor window and being caught on a ledge."

"We didn't find that there were sufficient problems to look at, or take any legal action, but that doesn't mean I won't still be having a discussion with them about their health and safety programme overall."

Stewart has met with the family to go over the decision not to prosecute.

"Obviously it was a fairly emotional meeting, we went through what we had found and how we had come to our decision."