The person who is believed to have entered the water near the ferry terminal in downtown Auckland has been named by police as 24-year-old James Harley David Jenkins.
On Monday morning, police confirmed a search was underway for a person near the terminal on the Auckland waterfront.
Det Snr Sgt John De Heer said on Wednesday police do not believe he could have survived.
Police first responded to reports about 4:35am, and the Police Dive Squad have spent the past two days searching the area.
The Coroner has been spoken to and the man's next of kin have been informed.
"Our thoughts and sympathies are with his family at this difficult time," Det Snr Sgt Der Heer said.
He said inquiries were ongoing to find out what caused Jenkins to enter the water.
"We are still hoping to speak with two men who were seen talking to him before he has gone into the water and ask them to contact police immediately.
"Anyone with information is asked to contact Auckland City Crime Squad on 09 302 6557."
Information can also be provided anonymously to Crimestoppers on 0800 555 111.