A scaffolding tower has given way at Mystery Creek near Hamilton, causing a large speaker at the Parachute Christian music festival site to crash down.
The tower, erected on one side of the main stage, buckled under the weight of speakers after they were hoisted into position by a crane.
Site manager Kirit Makan said nobody was hurt.
"One of the parts of the scaffolding frame was just bent up," he said.
"It just brought the speaker array down.
"Now we are looking at building a new tower with new scaffolding."
Makan did not expect the accident to delay the opening of the festival at 6pm tomorrow.
Makan could not say how many speaker arrays would normally be attached to the scaffolding, but it would be about a dozen.
In 2013 Great North bassist Rachel Donnell suffered head injuries at the festival when a chandelier made from glass bottles came crashing out of a tree.