Police said they needed to know how the victim received his injuries and asked those in the car on Kitchener St to come forward.
The victim is on holiday from Tonga and was due to leave in two weeks' time. His wife is flying over next week to be with him.
Several members of the public have already contacted police with information.
Police would also like to hear from anyone else who may be able to assist with the investigation.
Anyone with information is asked to contact Auckland City Police on 09 302 6400, or call CrimeStoppers anonymously on 0800 555 111.