A man driving a blue sedan was airlifted to hospital in a serious condition. Paramedics were able to treat a woman in a black sedan at the scene before she was taken to hospital in a stable condition.
Police said they’d both undergo mandatory testing and no one else involved needed further treatment.
Northbound traffic was being diverted at Ku-Ring-Gai Chase Rd and one lane was also closed southbound.
Police set up a crime scene and were investigating the cause of the crash.