Around 4.15pm on Thursday, a beige coloured Toyota sedan heading towards Canberra drove off the Barton Highway, down an embankment and crashed into the dry creek bed of Jeir Creek.

The accident happened near Casuarina Lane in Jeir.

The 21-year-old male driver was able to get out of the car and flag down other drivers for assistance.

The 31-year-old female passenger, however, had to be removed from the vehicle by the emergency services because of her injuries.

"The passenger was conveyed to a Canberra hospital and [is] being treated for fractures to her ankles and other injuries," Inspector Matthew Hinton of Yass Police Station said on Friday morning.

"The driver was conveyed to a Canberra hospital and is being treated for fractures to his arms and wrists."

Emergency services from Yass and the ACT attended the incident.

"Police are reminding motorists the big killers on our roads are speed, fatigue and driver distraction from mobile devices," Inspector Hinton said.

"It's not just your life you risk, it's the lives of your passengers and other motorists on our roads."