Emergency services were called to the scene near the intersection of State Highway 6 and Camphill Rd, about halfway between Albert Town and Hawea, just after 4pm.
It is understood a southerly squall that descended on the area at the time caused the tree to topple.
Police, Fire and Emergency New Zealand (Fenz) and bystanders worked to clear the tree from the road, while a temporary diversion was in place for traffic heading in both directions.
The vehicle is believed to have been travelling towards Hāwea when the incident occurred.
A Fenz representative said an unknown number of the vehicle’s occupants were flown by helicopter to Dunstan Hospital "for further check ups".
No further information about their condition is known.
The road was fully reopened to traffic about 4.50pm.
- By Regan Harris and Milo Long
