Emergency services were called the scene at Ourimbah on the Pacific Highway near Kangy Angy, after a four-wheel-drive crashed into a Commodore station wagon just before 9am.
Tuggerah Lakes Police District Chief Inspector Col Lott said initial inquiries suggest the station wagon became bogged on a median strip when a second vehicle lost control, and the two “unfortunately collided”.
Lott said the driver of the station wagon, a 46-year-old father, along with the passenger, his 27-year-old son, died at the scene.
The driver of the 4WD, a 27-year-old man, was uninjured.
“The matter is currently under investigation,” Lott said.
“The other driver has been admitted to hospital… he will be assisting police with our inquiries when he is discharged.
“This incident is traumatic for everyone but very, very traumatic for the family, losing both a father and a son.”
Police have established a crime scene and traffic diversions were put in place for southbound traffic on the M1.
Motorists were advised to avoid the area.