Searchers are scouring difficult terrain as they look for a hunter missing in Mt Aspiring National Park.
The 23-year-old Central Otago man was reported overdue from a solo chamois hunting trip in the West Matukituki Valley area about 10pm yesterday.
The man left on the trip on Friday and was due to return late yesterday afternoon.
Incident controller Senior Constable Mike Johnston of Wanaka Police said the terrain was "extremely difficult and hazardous."
"Our priority is to try and find any indication of the missing hunter."
"At this stage we are searching likely points, looking for any sign of the missing man, and seeking to eliminate as many possibilities as possible.
"Further teams are being placed on standby to be used if needed."
Wanaka police and land search and rescue members began their search after the Southern Lakes helicopter arrived from Te Anau overnight.
The helicopter is equipped with night vision equipment, a spotlight and winch.
Wanaka police search and rescue coordinator Senior Constable Mike Johnston said the focus of the search was on the areas the man had intended to hunt in the upper Rob Roy Valley and the southern face of Homestead Peak.
The conditions for night flying had been favourable with clear skies, light winds and good moonlight.
Searchers hoped the hunter had a light source that could be detected by the night vision equipment.
Another search team was on standby.