Both the men were injured.
"As a result of the attack, the second victim received multiple facial injuries, while the woman's boyfriend received a cut to his left eyebrow and swelling to the back of his head."
Police want to hear from anyone who could help to identify the man whose face is featured in the screen grab from the CCTV footage.
"He may be a foreign national from Australia or Russia."
Detective Adam Bicknell said any information from the public about the incident would be a huge help, as other avenues of inquiry had not revealed any information.
Information can go to Detective Adam Bicknell on (09) 213-8184, at adam.bicknell@police.govt.nz or anonymously via Crimestoppers on 0800-555-111.