A police spokeswoman confirmed ambulance staff were also responding.
Heavy rain is falling in the area and a Hawke's Bay Rescue Helicopter spokesman said the helicopter had been unable to make the journey due to the hazardous conditions.
Fire and Emergency NZ Hawke's Bay area commander Ken Cooper said a fire engine from Taupo was on the scene.
Two fire engines from Napier, along with a level-three advanced rescue team from Hamilton are also en-route to the accident.
Cooper said the two were trapped on the bank but not in the vehicle. They could be seen by rescuers, he said.
Cooper said the response was reasonably well coordinated, and it was "just a case of bringing the people to safety".
The road was closed as the rescue took place but opened at 11.50am.