ACT police want to speak to a man who allegedly used his mobile phone to film a woman in change rooms at a south Canberra shopping mall.

Police said the woman alerted staff at a department store at the Tuggeranong Hyperdome about 5:00pm on Wednesday.

She said the man had filmed her in the change rooms without her permission, and when she confronted him he became aggressive, before leaving.

The man was described as in his mid-20s, about 170cm tall with short brown hair.

He was wearing a dark top and cream-coloured pants.

Police obtained a CCTV image of the man and have called for anybody who recognises him to come forward.