A boy is fighting for life after a car driven by an 18-year-old P-plater slammed into a parked truck at high speed in Western Sydney. 

The 14-year-old was sitting in the front passenger seat of the Toyota Yaris when it crashed into the rear of the truck on Aviation Rd in Elizabeth Hills early on Saturday morning.

Emergency services arrived at the scene about 2.15am to find the car wedged underneath the heavy vehicle.

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Photos from the scene show extensive damage to the front of the Yaris, which remained lodged beneath its rear.

The boy was treated at the scene before being rushed to The Children’s Hospital at Westmead in a serious condition. 

The Yaris was left wedged underneath the truck. Credit: 7NEWS

The Yaris was extensively damaged. Credit: 7NEWS

The 18-year-old driver was taken to Liverpool Hospital for assessment and mandatory testing.

A crime scene has been established as police investigate the circumstances surrounding the crash.

Anyone with dashcam or CCTV footage of the incident is urged to contact Crime Stoppers.