Wellington Police are investigating a sexual assault in Tawa last night.

Police say about 7.25pm a woman was walking on Duncan Street when she was grabbed from behind by a man who then indecently assaulted her.

When she reacted to the male’s actions he ran south on Duncan Street towards Tawa College.

The victim was unable to see where he ran after that.

The male is described as about 1.7m tall and of medium build.

He was wearing a grey hooded sweatshirt and a pair of dark green camouflage knee length shorts.

Detective Sergeant Haley Ryan of the Wellington Crime Squad says Police are determined to find the person responsible and are asking for the public’s help.