Man charged after filming female employee

A man is fighting for life and another man has been charged after an assault outside a pub in Sydney's southwest.

The incident began about 11pm on Friday after a female employee left the East Hills pub and was approached by a 21-year-old man who began filming her on his phone, police say.

Two other men, 45 and 50, intervened and were attacked by the younger man who then fled, police said.

The 50-year-old was taken to Liverpool Hospital where he remains in a critical but stable condition on Monday, while the 45-year-old was treated at the scene.

Police arrested a man at a Penshurst home early on Saturday and charged him with reckless grievous bodily harm and common assault.

The man was refused bail and will face Bankstown Court on Wednesday.