Nobody knows how long 4-year-old Aldrich Viju lay unconscious on a daycare slide before an adult saw him and attempted CPR, a Coroner has found.

Aldrich died at Angels Childcare Centre in Takapuna on November 18, 2016, when he was strangled by a cord attached to a toy stilt while sliding down a plastic slide.

Coroner Sarn Herdson has released her decision following an inquest into the little boy's tragic death. She found the 4-year-old died due to the effects of hanging due to ligature from a cord attached to a toy stilt.

A Worksafe investigation found his death could not have been foreseen, and the centre was not prosecuted as it was not found in breach of its duty of care.

But the Coroner has recommended the risk of playground equipment presenting a strangulation hazard should be highlighted more widely to help prevent a future tragedy.

Aldrich had arrived at the centre during free play time. He had been at the centre for less than an hour when he was found unconscious on the slide. Evidence showed he had been sliding while carrying WePlay brand plastic "stepping stone" stilts with adjustable cords.

A cord had got stuck at the top of the slide and caught around his neck as he slid down, leading to him falling unconscious. Another child had quickly alerted two centre staff but efforts to revive him were unsuccessful.

But the Coroner's report says because the incident was not witnessed by an adult, there were "inevitable limitations" to determining what happened, including how long he was on the slide and when he became caught.

The Coroner also noted the findings of Worksafe's 2017 investigation, which found Aldrich's death could not have been anticipated by the centre.

Worksafe's report found the slide was of a type common at daycare centres around New Zealand, and it met safety standards. Similar stilts are also commonly used. The WePlay branded stilts are currently supplied with a safety warning label warning showing they should not be used by under-3s as the cord is a strangulation hazard. It's not known if that label existed when Angels Childcare acquired them, the report says.

There was an appropriate staff-child ratio in the playground, and the slide was in view of a staff member, but its high sides meant there was a blind spot if a child was lying down, Worksafe found.

The centre was also aware of strangulation risks - it had no dress-up box for this reason and children were not allowed to bring toys or capes from home. Toys were not allowed to be taken on climbing equipment - a rule that was regularly discussed with staff and children.

Worksafe did not prosecute Angels Childcare as it found the business was not in breach of its duty of care. (Photo / Chris Loufte)

In looking at whether similar incidents could be prevented in future, the Coroner endorsed Worksafe's 2017 hazard alert on managing strangulation hazards on playground equipment.

Any situation where a child has access to a rope or cord is hazardous, the alert says - pointing out children use toys in innovative ways, and may take them onto elevated play equipment. If a toy contains a rope or cord this means there is a risk of strangulation.

Childcare businesses should prevent children taking ropes or cords onto elevated play equipment where possible, and should be appropriately supervised - which may mean watching them at all times, the alert says.

Coroner Herdson recommended the alert should be considered for revising and republishing, and the Ministry of Education and SafeKids Aotearoa should be advised in order to bring these issues to wider attention.

Since Aldrich's death a child was injured at another childcare facility due to a strangulation hazard; the Coroner noted Worksafe had prosecuted in that case because the equipment did not meet safety guidelines.