Senior Constable Jeff Cramp, of Rawene police, said a man living nearby heard a loud grinding noise as the bottom of the Ford Explorer scraped along the lip of the bridge before falling in.
He jumped into the floodwaters - at that stage the river was just half a metre below the bridge deck - and fought to open the rear of the submerged ute but the current proved too strong.
The cause of the accident was not yet known, Mr Cramp said.
The Advocate understands the man who risked his life in the initial rescue attempt was a member of the Omapere Fire Brigade and knew the deceased.
The ute's doors were jammed against a submerged log on one side and held shut by the current on the other.
Volunteer firefighters and local farmers using two tractors eventually managed to pull the ute from the river.
A specialist investigator from the police Serious Crash Unit was at the scene yesterday.
It was raining heavily at the time but the bridge was still above water. During floods, its deck can be as much as 2m under water.
It is understood the man was visiting relatives on Hooks and Halls Rd to discuss arrangements for a family member's funeral.
Knowing the river's tendency to flood, he decided to head home before the bridge went under.
His death is another blow to the close-knit Omapere community and the Hokianga Harbour's volunteer Coastguard unit. He and his wife were key members of the Coastguard.
Police had yet to formally release his name at edition time yesterday.
In April, Omapere 14-year-old Robbie McKenzie drowned when the quad bike he was riding rolled into a drain at a family farm near Kaikohe.
His father, Callum, is also a key Coastguard volunteer. Robbie had just started boarding at Whangarei Boys' High School.
It is understood the one-lane bridge has no guard rails because they would trap debris during floods and put the structure under too much strain. Police may, however, recommend other measures to make the bridge safer.
Far North District Council infrastructure manager Jacqui Robson said the council extended its condolences to the family of the deceased motorist.
She said it was too early to speculate on the cause of the accident, and not helpful or respectful to do so until the Serious Crash Unit and the coroner had completed their investigations.
