Two men in their 20's has died following a two-vehicle crash near Yass overnight.

Just before 2am, NSW Emergency Services were called to reports of a motor vehicle crash involving a truck and car on the Hume Highway near Rock Lodge Road, Lade Vale.

Police have stated initial inquiries, suggested a passenger in the Mazda got out and was struck by a second truck, travelling northbound.

The passenger, a man in his 20s, died at the scene.

The driver of the car, a 23-year-old man was treated at the scene. 

A specialist medical team was flown in and extraordinary measures were used to stabilize the man with medical treatment procedures including three units of blood transfused. He was then able to be airlifted to Canberra Hospital in a critical condition.

However, despite the best efforts by medical personnel the driver died in hospital on Sunday evening.    

The two truck drivers, aged 32 and 65, were uninjured and taken to Yass Hospital for mandatory testing.

A crime scene was established and examined by specialist police from the Crash Investigation Unit.

Anyone with further information is asked to contact Crimestopers on 1800 333 000