Police said the crash happened at around 11.50pm on Tuesday on the A90 Aberdeen to Fraserburgh road at Auchiries, Longhaven, near Peterhead.
Two vehicles were involved, one a marked Police Scotland Peugeot Partner van and the other a blue Vauxhall Astra car.
At the time the Police Scotland van was being driven by a 46-year-old male dog handler who was on duty, along with two police dogs in the rear.
The Vauxhall Astra was driven by a 58-year-old man.
The Scottish Fire and Rescue Service and Scottish Ambulance Service also attended and both drivers, after being freed from their respective vehicles, were taken to Aberdeen Royal Infirmary for treatment.
The Police Scotland officer’s condition is described as critical while the other man is described as stable.
The family of the officer is aware.
Checks are urgently ongoing to trace the family of the other driver.
Road Policing Inspector Jon Barron said: “Our inquiries into the circumstances of this crash are obviously still at an early stage. I would be very keen to speak with anyone who may have seen either vehicle shortly beforehand, or anyone who witnessed the collision and who hasn’t yet been spoken to by Police. Please contact us on 101.”
The A90 was closed for several hours while collision investigators studied the scene and examined both vehicles. The road has since re-opened.
The police dogs were taken to a local vet for examination. One appears to be uninjured. The other does not appear to be seriously injured but is still being assessed.