The two-vehicle crash, involving a vehicle and a motorbike, was reported to emergency services at 5pm.
Both the motorbike rider and the sole occupant of the vehicle died at the scene, police said in a statement this morning.
An investigation is under way.
The highway was closed for several hours after the crash, leading to significant delays.
Hawksburn Rd, a back country route between Clyde and Cromwell, also had to be closed for a time owing to high volumes of traffic and multiple unsuitable vehicles trying to use it.
Thomson Gorge Rd, another alternative track not suitable for general use, was also closed, Fulton Hogan said last night.
Vehicles not suitable for the road had also attempted this route and were ''causing issues''. Fulton Hogan said it closed the road for safety.
- APL
