A 92-YEAR-OLD woman has been taken off the critical list after being attacked by her daughter's pit bull in Sydney's south.

A spokeswoman for St George Hospital says the elderly woman is now in a serious but stable condition after suffering head, neck, chin and ear injuries.

The woman was attacked by the American pit bull terrier in the driveway of a Sans Souci home on Good Friday.

Hearing screams, her 70-year-old daughter ran outside where she found her dog on top of her mother.

With help from a man and his son who were passing by, she managed to pull the dog off and lock it inside the house, police said.

While the elderly woman was taken to hospital for surgery, her daughter also required hospital treatment for cuts and puncture wounds to her hands.

The two men who helped the woman said they have never seen "so much blood".

"We thought the screaming was a fight or something so we did a light jog around the corner and there was a dog basically chewing a lady's face off," Justin Innes told Fairfax.

"I gave my son the six-pack (of beer) I was carrying and told him to stay back but the dog was going crazy. I was hitting it but I had nothing, so I told my son to give me a beer and I hit it with that.

"Then he (my son) came and hit it with the rest of the six-pack."

Mr Innes said the dog turned on his son Jacob before they were able to wrestle it back inside the house.