Samiuela Anania Tupou, 21, died at Seaside Park in Ōtāhuhu in the early hours of May 25.
He was found in critical condition and later died at the scene despite medical attention.
Stuff.co reports Tupou had just recently returned from the United States to live with his family in Mangere before he died.
No arrests have been made, police said.
Counties Manukau CIB detective senior Sergeant Malcolm Hassall said Tupou had no criminal history and they believed the offender was not known to him.
He said investigations were ongoing.
"Police are actively following lines of enquiry in relation to the offender or offenders involved," Hassall said.
They still wanted to hear from anyone who saw a light- or gold-coloured people mover, similar to a Honda Odyssey, in south Auckland on May 25 between 2am and 6am.
"Several members of the public have contacted police with information about this homicide investigation."
Tupou was described by friends and family as a fun-loving, hardworking young man.
Ma'ake Hauto, Tupou's former schoolmate from Salt Lake City in the US, said he always had a big smile on and was always willing to help others "no matter what".
Another friend Lavelua Pulu said Tupous was "just another older brother on the lookout", who would always check in on his friends.
Hassall said police are still encouraging anyone with information to get in touch with the Counties Manukau Police on 09 261 1321 or Crimestoppers anonymously.