Te Puke Volunteer Fire Brigade chief fire officer Glenn Williams said a former firefighter was driving past when he saw the crashed vehicle.
Williams said the former firefighter tried to stabilise the driver and keep him inside the vehicle until an ambulance arrived.
"The car had hit a couple of concrete fence posts and then gone into a tree," Williams said.
He said the car was a "long way" from potentially hitting any residential properties.
Acting Western Bay of Plenty head of road policing Senior Sergeant Wayne Hunter said the crash was still under investigation by the serious crash unit.