The man missing in Lake Wakatipu has been named as Matthew Charles Duncan, of Bluff.
Senior Sergeant John Fookes, of Queenstown, said Duncan, 46, went missing from his cabin boat, Sundance 2, on Sunday.
”Mr Duncan, known as Matt, is the owner of Painting Solutions and had been working at Queenstown,” Fookes said.
The Police National Dive Squad has arrived in Queenstown to assist with the search.
Fookes said divers would be searching an area from the Earnslaw slipway, where the boat set out from about 9.30am on Sunday, to near the Bay View Road boat ramp.
The boat had travelled “several hundred metres” from the slipway before stopping for a period of time. It has then either drifted or made its way towards the shore, Snr Sgt Fookes said.
It was not until late on Sunday afternoon that the boat was found to be empty and the man missing.
LandSAR and Coastguard personnel searched the shoreline and lake following the discovery on Sunday night.
The search was resumed on the water, around the shoreline, and from the air on Monday.