Fire and Emergency New Zealand (Fenz) shift manager Lyn Crosson said appliances from Mosgiel, Outram, Waihola, Wakari, Dunedin and Portobello were initially called to the fire about 4.30pm, because of concerns about the dry, windy conditions, and its proximity to bush and nearby transmission lines.
The area was deemed inaccessible to the Fenz appliances, so a helicopter with a monsoon bucket and a command unit were called soon after, she said.
The fire grew to 20m by 20m, and a large crowd of onlookers were ordered to leave the scene for their own safety.
No property was in danger and no-one was injured, she said.
The fire was extinguished by 7.20pm, but crews from Dunedin Central and the command unit remained in the area in case of flare-ups.
She said the fire was deemed suspicious and an investigation into the cause began last night.
