RCCNZ search and rescue mission coordinator John Ashby said strong winds and torrential rain in the area meant neither the Westpac Rescue helicopter, nor police land search and rescuers were able to reach the trio.
The family spent the night in cold and wet conditions but have now been rescued.
"They have had a cold wait in very uncomfortable, wet conditions but they had sufficient equipment for a four-day tramp and that has helped them get through the night," Ashby said.
"Without an emergency locator beacon to call for help, this would have been an extremely challenging situation for them."
RCCNZ spokesman Steve Rendle said the weather conditions had been "pretty terrible".
"They've had a pretty miserable night but they are now safe and back in warmer conditions."
The family was not at a hut so they would have been out in the open, Rendle said.
They had been picked up by a crew from Wairarapa-based Amalgamated Helicopters, who know the area well.
The crew dropped them off at Tutuwai Hut, further down the track, where they were picked up by the Westpac Rescue Helicopter.
They were then transferred to an ambulance waiting in Kaitoke.
Rendle said they were taken to the hospital at Trentham Army Base to be checked over. They were uninjured but two had mild hypothermia and one had moderate hypothermia.
