Driver 'distraught' after crash that injured grandmother

A driver charged over a crash that hospitalised a 79-year-old grandmother in Sydney's south-west was distraught at the scene, a witness has claimed.

Bridget Burchell was struck by a car on Oxford Avenue in Bankstown just after nightfall.

The driver stopped and immediately called Triple Zero.

"He was crying, he was really distressed," witness Isabelle Jabbour told 9News.

"He was saying, 'I wasn't drunk, I wasn't speeding, how can this happen'."

Ms Burchell was taken to Liverpool Hospital in a critical condition with a broken pelvis, leg and arm.

She is now in a stable condition but remains sedated.

It is believed Ms Burchell was crossing the road after her car broke down about 20 minutes before the accident.

Trong Nguyen, 31, has been charged over the incident and could face a possible seven-year jail term over the most serious alleged offence.