St Kilda police are hoping to identify a man after a woman was assaulted at a supermarket in Balaclava on 30 October, Victoria Police say.
Police have been told a woman was in a customer line at the checkout of the supermarket at the corner of Camden Street and Carlisle Street about 7.45pm.
A verbal altercation occurred between a male customer and the sales assistant ahead of her.
The woman intervened and the male offender punched her to the head, causing her to stumble backwards.
The 52-year-old woman from Hawthorn received serious head injuries.
The offender ran from the store.
He is described as Caucasian in appearance, 180cm tall, short shaved hair and was wearing headphones and dark clothing.
Investigators have released CCTV image of a man that may be able to assist with their enquiries.
Police are also keen to speak to any witnesses who were at the supermarket at the time of the assault.
Anyone with information is urged to contact Crime Stoppers.