The crime scene at Rookwood cemetery on Saturday. Credit:Top Notch Video

A 39-year-old man has died at Rookwood Cemetery in Sydney's west after he became trapped underneath his car while changing a tyre.

The man died of cardiac arrest just after emergency service workers arrived to Haslem Drive, Rookwood, about 10.15am Saturday police said. The man was found by a woman on her way to visit a grave in a remote section of the cemetery.

"She found the poor man screaming underneath the car and raised the alarm," the police spokesman said.

"It was a bit of a desperate situation however four of us lifted the car off him while the other two dragged him out. One of the ladies who found him helped do CPR until emergency services arrived," he said.