Charity collector sexually assaulted

The woman, collecting for charity, was called over by the group of men who went on to sexually assault her. Photo / Thinkstock

A woman doorknocking for charity has been attacked by three men and sexually assaulted in Melbourne.

The 20-year-old woman was doorknocking in Brunswick to collect money for charity when three men called her onto the footpath about 3.15pm on Thursday.

One man grabbed the woman from behind and sexually assaulted her before punching her in the face.

The woman ran off and was treated for minor facial injuries in hospital.

All three men are described as Caucasian and aged in their mid-20s.

One man was described as about 180cm tall with a thin build, brown hair, unshaven and wearing a white T-shirt and black shorts.

The second offender had ginger hair in a crew cut, distinctive blue eyes and was wearing a black singlet and navy jeans.

The third offender was also about 180cm tall and wearing a black hoodie, large distinctive plug-type earrings and a single stud labret under his bottom lip.

Police have released an image of one of the men they want to speak to.

- AAP