The blaze broke out in the eight-bedroom Maungawera Lodge, on SH6 near Albert Town, about 3.15pm yesterday.
The lodge had been rented to the Treble Cone Race Academy, which was accommodating 12 members of the Austrian ski team there.
Although some of the team members were at the lodge when the fire started, no-one was hurt, academy director Guenther Birgmann said.
''Three boys lost passports and all their belongings. They are left with the clothes they have on their bodies.''
The team members did not know how the fire started, he said.
The lodge is owned by the Gore-based Stewart family, which operates Leithen Valley Trophy Hunts.
It housed about 30 trophies collected by family members.
They included ''dad's grand slam'', Rachel Burke, said of her father Alan's four rare North American sheep.
''He is one of the very few, if not the only one, in New Zealand that have got it.''
The irreplaceable hunting trophy collection was hauled out of the lodge when the fire broke out.
Mrs Burke, who works as Leithen Valley's marketing manager and guide, said she and husband Olly had rented the lodge to the academy.
Mrs Burke did not attribute any blame for the fire and said the lodge was insured.
A fire inspector will examine the scene this morning.
Lake Hawea Chief Fire Officer Doug Brenssell said a Lake Hawea fire appliance and two from Wanaka attended.
The garage and storage area was ''fully involved'' when they arrived. A bedroom and hallway were also extensively damaged.
The still-full swimming pool provided a water source additional to the 20,000 litres from the appliances, Mr Brenssell said.
''I think we emptied half of that pool.''
