Two people are in a critical condition at the Canberra Hospital after a driver crossed into the oncoming lane of William Hovell Drive near Hawker in Canberra's west.
Detective Inspector Marcus Boorman said both drivers — both the sole occupants of their cars — were left with severe injuries.
"When you look at any collision that involves speed, it is a 90 kilometres per hour speed zone here, the injuries are going to be very severe," he said.
"I won't go into the exact nature of the injuries, needless to say, they are very serious.
"It is a very traumatic scene down there."
Detective Inspector Boorman said it took emergency services workers more than an hour and a half to cut the man and woman from their vehicles.
He said they had considered calling in a helicopter to airlift them because of the time it took, but ultimately the pair were taken to hospital in separate ambulances by police escort.
The road has been closed since the crash occurred, at about 7:30am, when the driver heading towards Belconnen crossed into the oncoming lane and collided with a driver heading towards the city.
Police are yet to identify ages of the drivers or any other details, as they wait to inform family and next of kin.
Sergeant Stephen Booth said investigations into how the crash unfolded were still continuing, and that the driver of a black SUV or 4WD in the area at the time of the crash could have crucial information.
"We're hoping that driver may have information or even dashcam footage that may help us with our investigation," he said.
"The driver was driving ahead of one of the vehicles involved, that is on the southbound lane of William Hovel Drive, and has been identified as narrowly avoiding the northbound vehicle."
