Queenstown Lakes Rural Fire Chief Gordon Bailey said the "textbook" fire appeared to have started on the roadside and could have been sparked by a cigarette flicked from a car.
The fire, on the northern boundary of Waitiri Station, took hold in scrub, and fanned by gusty northwest winds, it raced across the mountainsides of the Pisa Range and up into the Eastburn Stream gully, about 10km north of Cardrona.
A crew of 10 volunteers from the Wanaka Fire Brigade were first on the scene, about 1pm, after motorists called 111 to raise the alarm.
Rural firefighting teams were brought in from Arrowtown and Luggate, while two helicopters equipped with monsoon buckets worked to contain the fire.
Another helicopter was also on hand.
Ground crews were landed about 4pm to dampen mountainside hotspots.
Firefighters had extinguished the blaze by early evening.
Late afternoon showers in Wanaka moved south and up the Cardrona Valley to help dampen the area and give fire crews some respite.
About 20 people were involved with fighting the rural fire, Mr Bailey said.
The fire was 1km from entering the Pisa conservation area, administered by the Department of Conservation.
An investigator who visited the site was unable to determine the cause of the fire.
