McHugh said while the buildings were insured, the vehicles were not.
Fire crews arrived to find a "well-developed fire" at the car wreckers last Tuesday around 7.10pm . Within an hour, the fire had been upgraded to a fifth-alarm and 22 crews from across the region were at the scene.
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Smoke was billowing from the lot and could be seen as far away as the Mangorewa Gorge.
Fire and Emergency New Zealand incident controller Hamish Smith said the burning cars, equipped with combusting linings, seats, tyres and even oil, continued to light up at pace and the scene was "unpredictable" and hazardous, Smith said.
Not only that, but two large buildings filled with sawdust and dry timber bordered the blaze.
"There were a lot of potential risks," Smith said.
A firefighter on the scene said if it had caught one of the buildings, they could have been dealing with a catastrophic airborne fire.