The driver of a minivan involved in a fatal crash in Sydney's west on Tuesday afternoon was a disqualified learner driver, police said.

The 20-year-old woman was taken to Westmead Hospital following the crash and treated for abrasions, and police were waiting for approval from hospital staff to interview her.

The van, carrying six children and three adults, and a commercial van with one driver, collided at Mamre Road in Kemps Creek about 1.30pm.

A two-year-old girl died at The Children's Hospital at Westmead shortly after the crash.