The cost of fighting a large tussock fire in remote Central Otago hill country on Friday may be faced by the New Zealand Defence Force, as a simulated explosion during a battle exercise by the army is believed to have started the blaze.
The fire on the Shortlands Station pastoral lease, about 5km north of Danseys Pass Hotel, was close to the boundary with the Oteake Conservation Park.
Between 1sq km and 2sq km of tussock land was burnt.
Two helicopters as well as ground fire crews were used to fight the fire, but they all had to abandon the area four hours after the fire started because high winds, snow and hail made it too dangerous for them to continue.
Snow that evening and the following morning put out the fire.
New Zealand Defence Force army media spokesman Major John Gordon said the army was carrying out a large-scale exercise involving many activities, which included a group of soldiers in the Danseys Pass area on Friday taking part in a simulated battlefield exercise.
"We had all the consents and permits needed beforehand," Maj Gordon said.
During the battle simulation, small incendiary devices were detonated to simulate explosions and soldiers were trained to respond.
"It seems the detonation caused a spark and, in the conditions, it initiated a small fire, which rapidly spread, and became a matter for the rural fire authorities," Maj Gordon said.
"They were contacted straight away, given the nature of the conditions and the risk of the fire, and it appeared to have spread quickly."
Nobody was injured, he said.
Maj Gordon said the exercise involved 300-400 soldiers over a wide area through to Tekapo. It would finish in about 10 days and would continue as planned, but extra measures would be taken to mitigate against any more fires.
The contract with landowners entered into before the exercise began would cover details about the army's liability, he said.
Department of Conservation Central Otago manager Mike Tubbs said it appeared the army was taking responsibility for having started the fire. It was too soon to speculate on the cost of firefighting.
"If there were costs involved, usually they'd rest with the individual or group responsible for starting the fire, " he said.
At this stage, it appeared the only fire damage was to vegetation.
It was lucky the cold snap hit on Friday night, Mr Tubbs said.
"The snow did the job for us and, to all intents and purposes, it's put out the fire." The New Zealand Defence Force and rural fire authorities will be meeting soon to determine exactly what happened.
