US police have been filmed kicking an innocent man in the head seconds after he was engulfed in flames from a car accident.

His vehicle caught fire after another driver in a police pursuit crashed into it in New Jersey on Sunday night.

Video footage shows him rolling on the footpath after climbing out of the car, his shirt on fire.

After tearing off his shirt he was approached by half a dozen officers with their guns drawn.

As he kneels before them unarmed, a police officer kicks him in the face. Other officers then start stomping on his body.

"Our investigators have reviewed the video and we believe with certainty that this man is the bystander from West New York who suffered burns, not Leo Pinkston, the individual pursued by police," prosecutor Esther Suarez told the Jersey Journal .

Pinkston was fleeing from police when his car crashed into the unnamed 28-year-old's as he was returning from work.

Pinkston has since been charged with aggravated assault and eluding.

The victim meanwhile is in a critical condition with serious burns and broken bones.

"Taking swift action isn't always elegant, but this video clearly shows that the officers acted quickly to extinguish the flames, and pull this man out of harm's way," a police union spokesperson said.