It was an unprovoked attack, and the victim was a foreign national who has a limited support network in New Zealand, Matthews said.
The two men of interest were last seen walking down Grange Avenue.
The two men of interest are described as being of Māori or Pacific Island descent and about 21 years old.
They are of a large build, with curly black hair.
One of the men was wearing shorts, but with no shirt or shoes and the second man was shorter, and wearing shorts, shoes and a shirt.
Police believe the men in this CCTV image may be able to help with inquiries.