A woman has been sexually assaulted while walking her dogs through a cemetery in Melbourne’s west.

Police believe the woman was walking her two pets through the cemetery on Champion Road in Williamstown, when she was approached from behind by an unknown man on Saturday 29 June at 8.30pm.

The man - described as having a large build and was wearing a black puffer jacket and white beanie - pushed the woman to the ground and attempted to pull her pants down.

The victim’s dogs attacked the offender who fled on foot towards K.C. White Reserve on Park Crescent.

The woman ran home and contacted police who attended.

Police set up a crime scene at the cemetery and the area was forensically examined.

Detective Senior Constable Jenna Sladek from Westgate Sexual Offences & Child Abuse Investigation Team is appealing for anyone who knows anything about the incident to contact Crime Stoppers.

“We know people congregate at the cemetery at night so we are keen to hear from anyone who witnessed the assault or may have been in the area at the time,” she said.