One man has died in a car crash on a rural road last night.

Police said the crash, involving one vehicle, happened in Port Waikato.

"The male driver and single occupant of the vehicle died at the scene when the car he was driving failed to take a corner, left the road and went into the Waikato River," police said in a statement.

The Counties Manukau Serious Crash unit was at the scene near Tuakau Bridge, just west of Klondyke Road. The road was closed overnight.