A driver wanted over alleged domestic violence crimes has been flung from his car.

He had been attempting to evade police during a pursuit through the Western Sydney region, before a four-vehicle crash that left him fighting for life on Friday, NSW Police said.

The 33-year-old man was first spotted by police on Great Western Hwy at Bowenfels, driving a red hatchback on what 7NEWS understands was allegedly a disqualified learner’s licence, about 5am.

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WATCH THE VIDEO: Police chase ends in devastating crash for domestic-violence accused driver

“The man was wanted on two outstanding warrants for domestic violence related offences,” police said.

The car fled as police approached and lost sight of the wanted man, but patrols located the car about 7am on Werriway St at South Littleton.

“It allegedly rammed a police vehicle and drove at a police officer,” NSW Police said.

There were no reports of injuries after the ramming, but a police chase ensued shortly after on Bells Line of Rd but was later called off due to “due to the dangerous manner of driving”.

A second police chase began in Faulconbridge, but was again called off for safety reasons.

A police chopper tracked the car to Penrith, where the hatchback hit road spikes that had been deployed on Castlereagh Rd and Cranebrook Rd.

The red hatchback continued on Castlereagh Rd and smashed into a Toyota SUV, a Sprinter van, and a Hyundai.

The 33-year-old man was flung from the hatchback, and suffered serious head injuries.

He was treated at the scene by paramedics and then taken to Westmead Hospital in a critical condition.

The driver of the SUV — a 35-year-old man — was the only other person who was injured, and was treated for minor hand injuries.

A crime scene was established, and an investigation is ongoing.

Anyone with relevant information or dashcam footage is urged to contact Crime Stoppers.