Update: The road was expected to remain closed overnight, possibly opening around midday tomorrow, according to the NZ Transport Agency.
Fire crews, police and regional council staff have been working around the clock to clean up and recover a truck that crashed down a bank on State Highway 36.
The road remains closed this morning, more than 36 hours after a truck and trailer unit went over a bank at Mangorewa Gorge on Monday afternoon.
Crews were heading back out this morning worked to recover the truck and its hazardous substances.
A police spokeswoman was unable to say when the road might be reopened.
Megan Ruru, fire communications shift manager, said there were five fire engines from Rotorua on site yesterday, including a hazmat team.
She said they filled a precautionary role, to secure the hazardous substance and remove it before the truck would be removed using a crane.
She was unable to say what the hazardous substance the truck was carrying was, but believed it had been mostly contained in the drums.
Some had been spilt on to the road.
The driver, a 63-year-old man from Rotorua, died in the crash.
Diversions remained in place at the north end of Pyes Pa Rd near Te Matai Rd and the south end of Pyes Pa Rd near Dudley Rd.
An NZ Transport Agency spokesman said police might not open the road until this afternoon.
"There are detours in place, but we would like to ask motorists to avoid the area if possible."