A rescue operation was launched yesterday afternoon after the man reportedly went into the water while fishing in Glenorchy.
A police spokeswoman said police were contacted at 3.15pm about an incident near Benmore Pl, when a man was reported missing by his friend fishing a short distance away.
Police began the search and rescue operation supported by local resources.
A search of the shoreline was continuing this morning.
"Every support possible has been summoned," a police spokeswoman said.
The Police National Dive Squad was expected to be deployed later in the day.
Queenstown Lakes harbourmaster Marty Black said the coastguard and first responders from Glenorchy were involved in yesterday's search.
"There were a couple of boats out there for quite a while," he said.
The man had not been found by 8pm and the search was suspended.
"It’s not good news for anyone," Mr Black said.
