Helicopters had flown over the site and landed a few hundred metres away, he said. Part of SH6 was closed for a time, with traffic backed up right to Gibbston.
But about 2pm, the NZ Transport Agency/Waka Kotahi advised that highway was open under stop/go traffic management and continued delays could be expected.
Police asked motorists to have patience while the backlog clears.
The police's serious crash unit was at the scene this afternoon.
There had been up to 25 emergency service personnel at the scene during the day.