A motorcyclist is in a critical condition following a crash at Alpine near Mittagong.
Just after 4pm, Emergency services were called to the Hume Highway near Church Avenue after a Volkswagen Golf station wagon and Honda motorcycle crashed.
The rider of the Honda, a 44-year-old man, was treated at the scene before being airlifted to Liverpool Hospital in a critical condition.
Meantime the driver of the Golf, a 45-year-old man, wasn't injured and was taken to hospital for mandatory testing.
Police and the crash investigation unit attended.
Anyone with dashcam footage or information is being asked to contact police.