A navy dive team will begin searching for a missing pilot in Central Otago on Tuesday.
Morgan Saxton, 31, of Haast, went missing on Saturday night and his Robinson R22 helicopter is believed to have crashed in the south-eastern arm of Lake Wanaka.
Searchers combed the shoreline and surface of the lake on Monday, focusing on an area where an oil slick and debris from Mr Saxton's helicopter have been found.
However, nothing more has been found and the land search has been scaled back.
Police say the dive team will take over, and admit they are now searching for Mr Saxton's body.
A large commercial barge is in place for use as a staging platform, with divers bringing in special equipment to search under water, including sonar.
Wanaka land search and rescue spokesperson Philip Melchior says the depth of the lake, which measures up to 300 metres, will make for a difficult search. The weather in the area has been choppy and is expected to get worse.
Mr Saxton is on bail pending an appeal, after he and his father, David, were jailed for stealing hundreds of thousands of dollars worth of Ngai Tahu greenstone from south Westland. They were released from prison in June.
Friends of Mr Saxton describe him as a very experienced pilot. In a statement on Monday, the Saxon family thanked searchers and the public for their help and support.