Police are continuing with their investigation into the incident which took place last Thursday near Melling, on the eastern side of the Hutt riverbank.
The woman in her early 30s was attacked about 1pm as she was walking northwards along the riverbank walkway from Melling, near Mills Street, Detective Sergeant Nick Pritchard of Hutt Valley CIB said.
He said police were now reviewing CCTV footage and other relevant information obtained as part of their ongoing inquiries.
"After reviewing the footage we are interested in speaking with a man who appears on camera in the Mills Street area just before 12pm, who as yet we have been unable to identify.
"Despite our inquiries to date, we have not been able to identify this person, so we are now seeking the public's help in the hope that someone can tell us who he is, or that he himself will come forward.
"We have therefore today made the decision to release images from the footage in the hope that we can identify and locate him, and if nothing else, eliminate him from our inquiries."
Mr Pritchard said at this stage the man in the footage was simply a person police wanted to speak to, as he may have information which would assist them.
Footage showed the man walking northwards along Connolly Street, Melling, at 11.42am before turning into Mills Street, then waiting for a few minutes by an access gate into the riverbank area at the end of the street.
He then reappears briefly by the gate again at 11.49am and 11.51am before disappearing from view, Mr Pritchard said.
The images also show a tattoo on the man's right calf.
Anyone with information could contact Hutt Valley Police on 04 560 2600, or Crime Stoppers, on 088 555 111.
