A woman has been rushed to hospital in a critical condition after her car was crushed in a crash involving two trucks in Sydney's south-west.

Emergency services were called to Henry Lawson Drive in Milperra just before 11am on Wednesday, following reports of a collision between two trucks and a Hyundai sedan near Fromelles Avenue.

Henry Lawson Drive is closed in both directions at Milperra following a crash involving two trucks and a car. Credit:Nine News

Seven ambulance crews including a specialist medical team rushed to the scene and began treating the 31-year-old woman for head injuries.

She has since been taken to Liverpool Hospital in a critical condition, a NSW Ambulance spokesman said.