Girl critical four days after Sydney fall

A five-year-old girl remains in a critical condition four days after falling from an apartment window in Sydney's west.

The girl and her three-year-old brother tumbled from the window of a third-storey apartment in Bankstown on Sunday morning.

Footage from the scene showed a window with a torn fly screen next to the top of a bunk bed in the apartment.

The young girl reportedly fell first and the boy on top of her.

She suffered life-threatening injuries and remained in a critical condition on Thursday, a Westmead Children's Hospital spokeswoman said.

The boy received minor injuries and is still in a stable condition.