The Rescue Coordination Centre New Zealand (RCCNZ) launched a search for the Robinson 22 helicopter about 3pm, after it was two hours overdue.
The chopper was on a training flight from Wanaka to Haast and back, with a trainee pilot and instructor on board.
Helicopters searching with night vision equipment last night picked up faint signals from an emergency beacon in the area, Maritime New Zealand spokesman Nick Churchouse told NZPA.
Searchers have since managed to get increasingly strong signals from the beacon, and have narrowed down the search area around 3km southwest of the pairs' last known position.
The search today would focus around Bow Peak in the Waipara Saddle, he said.
"With it now being daylight, they'll have a much greater chance of being able to see any signs of the helicopter."
Mr Churchouse said three helicopters would drop off ground search and rescue teams in the area this morning.
Weather is reported to be good for the search.
Helicopters from Wanaka, Southern Lakes Helicopters and Helicopters Otago were involved in the search, he said. Wanaka Helicopters has been training pilots for 31 years.
The company was involved in a fatal accident in 2006 when Wanaka-based pilot Keith McKenzie (29), of Canada, and his passenger, American tourist Jonathan Stein (61), were killed on a private sight-seeing flight.
The Robinson 22 they were in crashed at Homestead Peak near the Matukituki Valley.
