Wanaka police sub-area commander Senior Sergeant Allan Grindell told the Otago Daily Times police had reports of ''treacherous'' conditions on the Queenstown side following rain.
A motorist reported to the Wanaka station the road was ''as slippery as ice'', he said.
A second car overturned about 5km on the Wanaka side of the summit.
Sen Sgt Grindell said the occupants were taken to the Lakes District Hospital by passers by and no-one was at the crash scene when police, fire and ambulance arrived.
The third crash was of a car that spun into a bank on the Queenstown side of the summit, but did not overturn. No-one was hurt.
A motorist who passed the two overturned cars while travelling from Wanaka to Queenstown about 2.30pm said the road was dry at that stage, but there was low cloud on the Queenstown side.
