The Thames-Coromandel Council (TCDC) has been sentenced for its part in not keeping people safe in an inflatable slide collapse in Whangamatā in 2020.
Twelve people, mostly children, fell from heights of up to 12 metres in the incident. One man broke an ankle, and has required 11 operations since.
The slide was being used at the Whangamatā Summer Festival in Williamson Park.
The council was sentenced in the Tauranga District Court but was not fined. It has to pay reparation of $10,000 to the injured man.
WorkSafe's area investigation manager Paul West said the TCDC was convicted for its failures to manage a shared risk.
"Over and above the operator's obvious failures, the council plainly failed to do its due diligence on an operator with a poor safety record."
After the incident, experts found the slide was electrically unsafe, had air leaks via holes and seams, and poor anchoring.
Last year the operator of the slide, JTK Trustee Limited, was fined $350,000 and ordered to pay reparation of $40,000 over the incident.
WorkSafe found JTK applied to the council using an old form which did not require confirmation the slide met safety standards.
A permit was given three days after JTK applied, without the council doing any of the checks recommended by its own staff.
"Businesses and organisations that consent and permit events and equipment cannot absolve themselves of responsibility for health and safety when things go wrong. Whānau should have the confidence that public events they attend are being run in a safe manner," said West.
The maximum penalty is a fine not exceeding $100,000.