Police investigating the death of a man who drove off a Coromandel bridge last week say they have "more questions than answers".
Emergency services rushed to the scene of the crash at a one-way bridge on Purangi Rd, Whenuakite, in the Thames-Coromandel district about 9.46pm on October 29.
Police have identified the man who died as 27-year-old Benjamin Charles Rose.
Waikato road policing manager Inspector Freda Grace said another motorist came across the scene shortly afterwards.
"A motorist driving on to a bridge was unable to avoid debris and suffered two punctured tyres and on investigating he saw the brake-lights from a vehicle semi submerged in a stream," she said.
"This incident is still under investigation by the serious crash unit who are working to determine what occurred."
Mrs Grace said initial indications showed Mr Rose was travelling north on Purangi Rd, towards Cook's Beach, when his vehicle failed to negotiate a bend and went through a wooden barrier immediately before the bridge.
The car flipped as it dropped into the stream, she said.
Police were waiting for toxicology results to determine if alcohol played any part in the crash and were checking the road-worthiness of the vehicle, as it had not been registered or held a warrant of fitness since 2012.
"While expressing the police's sympathies to Mr Rose's family, it's still important to highlight the need for both vehicles and drivers to be fit for the road at all times.
"To not be at your best or by being behind the wheel of a vehicle that is not certified as road worthy can put your life, and the life of other road users at risk and it's simply not worth it," Mrs Grace said.