"At this stage the evidence strongly points to the driver being Mr Young. However, inquiries are continuing in relation to this crash," a police spokeswoman said.
Mr Young's father retired last year after 26 years as a judge in the District Court, High Court and the Court of Appeal, Fairfax reported.
A tribute page has been set up for Ben Young, saying he was a "much loved husband of Carmin and father of Maisie, beloved son of Glen and Ron, loved stepson of Kate..."
It is understood he had a 5-year-old daughter.
His funeral will be held this week and the family have asked people to donate to the Life Flight Trust, whose Westpac rescue helicopter plucked to safety three passengers who had clambered onto the vehicle's roof following the crash into the river.
Ben owned Wellington's Landmark Homes with Carmin.
On Saturday, the Westpac helicopter carried out a complicated rescue to pull the three survivors to safety.
Winch operator Julian Burn said the crew had to avoid getting too close to the trio in case the 110km/h winds generated by the helicopter's rotor blades blew them off the car and into the swollen river.
The pilot positioned the chopper about 25m above the partially submerged vehicle while Mr Burn lowered a paramedic.
The paramedic attached a harness to the survivors one by one and hauled them up.
"They were cold and they were very emotional because they had just lost their friend," Mr Burn said.
"It was the hardest one [rescue] I've ever done, just due to the factors: night-time, on the roof of a car, in a swift river, limited space, poor weather.
"But the pilot and the paramedic and the guys on the ground all did a fantastic job."
