An 18-year-old driver died after his car crossed the centre line on a slippery 75km/h bend near Te Kuiti yesterday morning.
The female driver of the other vehicle had minor injuries and was taken to Te Kuiti Hospital as a precaution.
Sergeant Chris Greenwood said the two cars - a BMW X5 and a Subaru Impreza - were probably write-offs.
Police were urging all drivers to slow down in the weekend's wet conditions and to be extra vigilant in busy traffic leading up to Christmas.
Meanwhile, the driver of a truck that dropped a load of tallow on a Kaimai Ranges road yesterday is being investigated by police.
Senior Sergeant Rob Glencross said the yellow animal grease made the busy stretch of road between Matamata and Tauranga impassable.
Motorists, many of them holidaymakers, were forced to go through Rotorua or Waihi, adding around an hour to the trip.