The man is described as a Caucasian, clean-shaven, in his early 20s, of slim build and about 1.7m tall. He had short straight brown hair and brown eyes. He was wearing a blue checked long-sleeved shirt, black jeans and a yellow plastic watch on his right wrist.
Mr Leonard said it was imperative that police identified the offender.
"Someone will know who this person is and we encourage anyone to come forward with information.
"The description is quite specific and he was wearing some quite distinctive items, which someone may recognise," Mr Leonard said.
Anyone with information about the offender or who saw the incident should contact Napier police on 06 8310700. Information can also be left anonymously on Crimestoppers 0800 555 111.