"It's a very basic little one room, and it's been pretty much destroyed," Paradise Trust chairman Tom Pryde, of Queenstown, said yesterday.
"There are wee bits of wall standing ... the reality is, it's unlikely [it can be saved].
Insurance was academic as it was only a little building, he said.
The cabin, used by families working the Paradise scheelite mine, was believed to be 103 years old. The estimated 7m long by 3m wide single-room, dry-timber dwelling was not supplied with electricity.
The cabin had been occupied on Sunday night by a young couple from Auckland. No-one was hurt in the fire.
Acting Glenorchy Deputy Chief Fire Officer Lindsay Jones said the school house was "well and truly alight" when they arrived.
It took 20 minutes to extinguish the fire and longer to dampen hotspots.
The Queenstown Volunteer Fire Brigade was called, as it was a structural fire. However, the fire was under control by the time it arrived at Glenorchy Fire Station and it was stood down.
