Late-night road deaths in NSW

Two men have died in separate crashes in NSW overnight, one in an allegedly stolen vehicle in the Blue Mountains and the other after hitting a tree in Sydney's west.

A taxi, which was allegedly stolen at knifepoint 20 minutes earlier in Lithgow, collided with a truck on Bells Line of Road at Bilpin around 10:00pm.

Police say the taxi's male driver, who has yet to be identified, died at the scene. Bells Line of Road remains closed.

In the second crash, a 20-year-old man died when his Mitsubishi left the road and struck a tree in Rhodes at 11:20pm.

The driver died at the scene while his female passenger was taken to hospital.