Salvage crews have recovered half of the truck and trailer unit which crashed off State Highway 1 near Kaikoura on Wednesday but there is still no sign of the driver.
The truck, carrying hazardous materials, crashed about 20 metres down a bank in the Hundalee Hills near the intersection of Claverley Road about 5.30am on Wednesday.
Police believe his body may be in the wreckage but intensive searches, including the use of an infra-red camera, have found no sign of him.
Rescue teams and salvage crews were back at the scene early Thursday morning.
Officer in charge, Sergeant Graeme Crosson, said a crane had winched the trailer back up to the roadside and the remainder of the vehicle will hopefully be recovered Thursday afternoon.
He said it was believed the man was lying deep in the wreckage or underneath the truck but he has not yet been found.
Sergeant Crosson said given the damage to the truck and very low temperatures it was unlikely the driver was still alive.
He said the man's family, who are based in Christchurch and Auckland, have been notified but have not been to the crash site.