Senior Constable Jim Jordan, of Milton, said the car was travelling east and downhill when it came upon the Milton-based Advantage Spreading Ltd fertiliser truck, coming in the opposite direction.
They were travelling on a gravel road and approaching a tight corner.
"The truck [driver] has done what [he] could to avoid [the collision] by driving up the bank," Snr Const Jordan said.
The truck and car collided, with the truck rolling and spilling its load of fertiliser.
The car driver had to be cut from the wreckage.
The Commercial Vehicle Investigation Unit and a vehicle safety inspector were conducting scene examinations yesterday. rachel.taylor@odt.co.nz