A man is in hospital after he was repeatedly stabbed while trying to defend a woman in Liverpool in Sydney’s south-west.

The 44-year-old man was found stabbed in the chest at Macquarie Street in Liverpool about 2.20am.

Police have been told the man was stabbed multiple times after he tried to intervene when he saw a man assaulting a woman in a parked car.

He was not known to the other man or woman.

The victim was treated at the scene and taken to Liverpool Hospital in a stable condition.

Police say the woman had already been assaulted in a car before the good Samaritan stepped in.

No one has been arrested over the attack.

An investigation is under way and anyone with information or footage of the incident is urged to contact police.