Police mentioned the 20-year-old lady was strolling with mates close to the intersection of King and Lonsdale streets about 5am on Sunday, Could 8 after they had been approached by a gaggle of males.
"It is understood one of many males then groped on the sufferer's backside sexually assaulting her. An altercation broke out between the teams earlier than the sufferer was subsequently struck to the face with an open palm," Victoria Police mentioned.
The group of males then walked in direction of Lonsdale Avenue, and the lady was taken to hospital with bruising and concussion, police mentioned.
Police have launched pictures of a person they imagine may assist help with their investigation.
The person is perceived to be of Pacific Islander/Maori look, with shoulder-length darkish hair in bunched, dreadlock-type curls.
He was carrying a light-weight blue t-shirt, light denims, and had a darkish beanie tucked into the entrance of his denims.