A Wanaka man who sunk out of sight last night after falling off a yacht on Lake Wanaka is presumed dead.
Police search and rescue (SAR) officer Sergeant Aaron Nicholson said Trevor Lloyd Hawke set out sailing with an associate just after 6pm last night.
He said the 70-year-old fell out of the yacht while sailing in Roys Bay on Lake Wanaka, Otago.
"The yacht he was in lurched unexpectedly and Mr Hawke fell into the water. Mr Hawke's associate rounded the yacht a number of times to try to pick up Mr Hawke but unfortunately he could not make it back onto the vessel and was seen to sink under the water and out of sight."
The Wanaka Yacht Club holds a twilight race series each Thursday during summer, but last night's racing was understood to have been cancelled because of choppy lake conditions.
Some people ignored the cancellation and ventured out, it is understood.
A police spokesman last night said Mr Hawke was wearing a lifejacket but it was not inflated.
A combined search effort between members of the Wanaka Yacht Club, Wanaka Police, Wanaka Coastguard and Land SAR members combed the waters of Roys Bay until night fall night in a effort to find the missing man's body.
Sergeant Nicholson said given the time that has elapsed since Mr Hawke was last seen, there was little hope of survival in such cold waters.
He said Mr Hawke's family had been "shocked" when told of the accident, and were grieving at the news.
Police will continue with a sonar search today, focusing on the area he was last seen.
The force will consider the use of the Police Dive Squad to try to recover the body.