Witnesses are being sought in relation to the repeated assault of a woman around the University of Otago campus.

The woman was assaulted several times by a male associate in the Harbour Terrace and Dundas Street area about 3.30am on Saturday.

A couple of witnesses spoke twice to the victim to ascertain if she was alright.

But after they'd left, the woman was again assaulted by her male associate.

Another witness helped her and contacted police, who arrested the offender.