The crash involved a car and a truck, police said earlier, and happened near the Tarawera Cafe.
Police were continuing their inquiries.
Napier traveller Karen Crawley, who was on her way to Hawke’s Bay from Ruapehu, was trapped in the queue west of the crash site since before the arrival of the first emergency services. She said: “It’s wet and miserable and my heart goes out to all those involved”.
“The visibility is very poor, and if it wasn’t raining it would be nice to get out and stretch,” she said.
Other motorists said fog had caused problems with visibility on the highway earlier in the morning.
As torrential rain fell early in the afternoon Crawley said most southbound cars appeared to have turned back towards Taupō, and the queue was mainly trucks.
The speed limit of 80km/h, installed on the highway three years ago, reverts to 100km/h at 6am on Thursday.
Emergency services on Wednesday afternoon also went to another collision involving a truck in Napier about midday.
The second vehicle in the crash at the intersection of Niven and Wakefield streets, in the Onekawa Industrial District, was a ute. Police said soon afterwards there were no injuries.
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