A fatal crash on the Karangahake Gorge may have been caused by a fallen boulder, police say.
A man driving a Holden Commodore died after crossing the centre line on State Highway 2 near the intersection with Rahu Road and collided with a car travelling in the opposite direction about 10.40am.
Inspector Freda Grace, road policing manager for Waikato District, said it was too early to confirm what caused the crash, but a large rock seemed to play a part.
"What I can say however, is that we are looking into what part, if any, a large rock similar in size to a medicine ball found in the eastbound outside passing lane may have played in the crash.
"It appears the man driving the Commodore may not have seen the boulder and struck it causing his car to career into the path of the Peugeot."
The man died at the scene and a female front-seat passenger in the Peugeot suffered serious injuries and was flown to Waikato hospital.
Mrs Grace said the gorge had been closed since the crash and this had put a strain on other roads in region.
"SH2 is a key route through our district linking the Ports of Tauranga and Auckland and is used by high numbers of heavy vehicles.
"Drivers are advised to expect delays and exercise caution and patience while using this alternative route," Mrs Grace said.
This was the third serious crash to occur on the stretch of road in just three days.
SH2 was closed through the Karangahake Gorge yesterday morning following a serious incident in which a car crashed into a paddock about 7.50am.
A person was rushed to hospital in a serious condition following the accident.
Another crash closed the highway on Tuesday, when three men travelling to Tauranga were in a car that rolled between Waihi and Paeroa.
The men escaped serious injury.