The police, the Rotoma Fire Brigade and a Rotorua District Council representative all attended the scene, to ensure the waste was disposed of correctly.
Council engineering services manager Andy Bell said it appeared the tailgate on the truck hadn't sealed properly and started "leaking sludge".
Mr Bell said the driver realised he was leaking waste on to the road and stopped in Rotoma. The truck dropped about a cubic metre of waste.
Mr Bell said: "We have contacted health authorities and have sent clean up trucks to help out. It shouldn't take too long to clean up."
EcoCast manager John Fell said the truck had been on its way from the Rotorua waste water treatment plant to the company's worm farm at Kawerau.
He confirmed a tailgate had broken and despite the presence of safety chains a "couple of wheelbarrows" of waste had leaked.
Mr Fell said they conducted weekly checks on all their trucks, which made multiple trips on the highway every day.
"It's a freak occurrence," he said. "I'm not too sure what happened yet."
EcoCast would investigate.
- Rotorua Daily Post