He was between Ingestre St and Guyton St.
Police say the incident happened as party-goers left bars and headed home.
Police inquiries to date include interviewing numerous witnesses to the assault. Detective Constable Mullany wants to speak to more witnesses.
"Our inquiries suggest that there are many more people who witnessed the assault and may have videoed the stabbing on their cellphones. We are interested in talking to anyone else who can help us with our investigation," he said.
"The victim was rushed to Wellington Hospital for emergency surgery shortly after the assault. He remains in hospital."
Anyone with information can contact Mr Mullany directly on 021 191 5473 or through Crime Stoppers 0800 555 111.