Fire and Emergency 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 manuka, bush, a steep face, and nearby transmission lines.
The area was deemed inaccessible to the appliances, so a helicopter with a monsoon bucket and a command unit were called soon after.
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, she said.
The fire was extinguished by 7.20pm, but fire crews would remain in the area in case of flare ups.
She said the fire was deemed suspicious and an investigation into the cause began this evening.
