Man found severely hypothermic, without trousers in Ureweras after weeks in bush would 'have been lucky to survive through the night'

In an unlikely tale of survival, a trouser-less man suffering severe hypothermia was found huddled in the foetal position near a hut in the Urewera Ranges.

The man was spotted in a clearing 20 metres from a hut between Te Waiotukapiti Hut and the Waiau River after activating a beacon yesterday at 2.30pm, Greenlea Rescue Helicopter said in a statement.

The man, who had severe hypothermia but was otherwise unharmed, ran out of food four days ago and was likely trying to walk alongside the river when he was swept downstream by a "muddy, raging torrent" while trying to skirt it to safety, pilot Nat Every told 1 NEWS.

A Greenlea Rescue Helicopter crew re-dressed the man in dry clothing and a sleeping bag before being airlifting to Taupo Hospital.

He has since been treated and discharged.

The man would "have been lucky to survive through the night" due to his "semi-naked" and the quickly deteriorating weather conditions, Mr Every said.

"He was reaching the point where he was getting confused."

Once the man was wrapped in an electric blanket he thanked the helicopter crew multiple times and serenaded them with a delightful song, Greenlea Rescue Helicopter said.