Senior Sergeant Maui Aben said police had not yet spoken to the driver, who was still in Gisborne Hospital.
It would be two weeks before the results of a toxicology report would be known. Until then police could not say whether alcohol was a factor.
Ms Smith's body has been taken home to Mangatu Marae, where the Whatatutu community was preparing for her farewell.
Family members from overseas and around the country were arriving to say goodbye to the young mum who was described as caring and loving, with a beautiful smile.
Her father, Tom Smith, said everybody was at a loss regarding the death: "Not just us but everyone, including the other families."
A couple who live next to the crash scene have been praised by police for their part in pulling the driver free and stopping the fire from spreading.
Jessica McMillan, who is five months pregnant, and her partner Matt Butler were watching a movie when they heard an explosion outside.
Mr Butler dragged the driver to safety, then went back with others who had arrived.
"We could see the fire starting in the front. It was just some little flames coming from under the dashboard," he said.
"We knew we didn't have much time."
Matt and another person climbed through the Explorer's boot to help a back-seat passenger but were still unable to get to him before the fire took hold.
"There was nothing we could do. It was fully engulfed in 15 seconds."
The couple attached Ms Smith's van to their ute and dragged it away so it would not catch on fire.
The crash extended the horror run on Eastern police district roads. It was the third multiple-death crash in the Northern Hawke's Bay and East Coast areas this year - the three worst crashes in New Zealand in the past three years.
The first was on SH2 between Raupunga and Wairoa on January 25, in which two teenagers and two men died. The second crash killed four men when a vehicle hit a tree off Waikare Rd, east of the SH2 settlement of Putorino, on June 2.
