A man described as chubby and Asian in appearance allegedly masturbated in the lingerie section of Target in the Canberra Centre on Sunday afternoon.
Police called for public assistance to identify the man after receiving multiple reports of his "act of indecency" about 1pm.
When a person observed the man in the act and walked to the front counter to contact security, the offender followed behind. The man then left the store and the Canberra Centre and walked towards Cooyong Street.
Police have described the man as 150cm tall with black short hair. He was also wearing a black cap, blue jeans and a light grey hooded jumper with 'I love NY' on the front.
Anyone with information about the incident can contact Crime Stoppers on 1800 333 000.
Information can be provided anonymously.