McIntosh said a dog that was also in the car survived. He did not know the victim personally, but McIntosh said he believed the man had purchased a section in the town about a year ago and he would "come and go".
McIntosh said the floodbank at the end of Wanganui Flat Rd was about 3m to 4m above the water.
"We put a ladder from the bank out to the the upturned vehicle in the water, and the police took over from there," McIntosh said.
Despite heavy rain overnight, the river was not dirty or in flood. McIntosh said the "horrible" accident was "another blow for the community following a series of sad events".
In March, a man working on a farm died when a tree fell on a digger, crushing the cab.
In November last year, another local died in a powered parachute crash at the Poerua River.
West Coast police response manager senior sergeant Brent Cook confirmed one person had died after a vehicle ended up in the river.
Cook said the focus of emergency personnel at the scene was to recover the vehicle from the river.
"There is a heavy rain warning out and we are working on ways of getting the vehicle out of the river as promptly as possible.
"As we all know, West Coast rivers are calm and benign one minute and then they rise rapidly. With the bad weather forecast we need to work out a way to recover the vehicle and the deceased safely," Cook said.
The investigation was still in its "early stages" and emergency staff — including police, fire and the Roa Mining Rescue Helicopter — were on the scene "promptly".
"We had some staff in the area, who ... were at the site of the incident very quickly."
At around 2.45pm police confirmed that both the driver's body and the ute had been recovered.