CCTV footage has captured the moment a shirtless man allegedly knocked an elderly woman unconscious outside a shopping centre in Melbourne’s west.

The 92-year-old woman was walking on Douglas Parade in Williamstown about 12.20pm yesterday when a shirtless man allegedly swung his arm at her, hitting her in the head and causing her to fall to the ground, according to Victoria Police.

The woman was knocked unconscious.

A CCTV camera caught the moment the man approached the woman before she fell to the ground. 

He is then seen walking away as she lies on the ground. 

The woman was taken to hospital in a stable condition with non-life-threatening injuries, Ambulance Victoria said.

Members of the public rushed to restrain the 39-year-old man, Victoria Police said. 

The man, who has no fixed address, was arrested when police arrived on scene and has since been charged with intentionally causing injury.

He will face Melbourne’s Magistrates Court today.