The road had been closed since Wednesday afternoon between its junction with State Highway 6 - at the bottom of zigzags - and at Cardrona township, south of Wanaka. It reopened at 3.30pm today.
A Queenstown Lakes District Council spokesman thanked motorists for their patience.
The council property and infrastructure senior engineer, Andrew Edgar, said earlier a helicopter sluicing operation yesterday did not move the rock, but confirmed its potential danger to road users.
"This boulder is sitting on a house of cards. Not only does it look like it could move at any time, but it's also highly likely to come down if any of the rocks below it move.
"Given its size, shape and the angle it's perched on, it could easily roll down on to the road with enough force to crush a car,'' Mr Edgar said.
A rock explosive and "rope access professional'' used explosives this morning to dislodge the boulder and break it up.
Debris was then be removed from the road so it could be reopened.
