The New Zealand Defence Force is helping search for a 49-year-old British man who has failed to return from a tramping trip to the Tararua Ranges.
A Royal New Zealand Air Force NH90 helicopter was sent at first light today to fly 27 personnel from New Zealand Land Search and Rescue (LandSAR) to the Tararuas.
"We remain on standby to provide further assistance if required," Air Commodore Tim Walshe said.
Sergeant Tony Matheson from New Zealand Police said the man left to hike from Levin to Masterton over the Tararua Ranges.
His partner contacted police when he failed to return home on Saturday afternoon.
About 50 searchers from police, LandSAR and NZDF, as well as a local helicopter, are looking for the man.
The man's overnight stay in the ranges would have been a chilly one, with wind chill temperatures dropping to -10C.
Metservice meteorologist Kyle Lee said for much of yesterday and last night, it was pretty wet and windy in the area.
"We had gales about the tops for the overnight period, so it was pretty strong in the exposed areas - as well as snow expected down to the 900m mark.
"That all continued through the night, and eased up in the early hours of this morning as the sun came up.
"The overnight period is pretty cold. A couple of the stations up there did freeze so they stopped reporting, while some of the huts in the upper regions got down to -1C, with a wind chill factor of -10C."
Lee said the forecast tonight is for cloud and some isolated showers.
Police search and rescue teams completed a search of huts in the area as well as an initial aerial search yesterday.
The search comes after a woman caught in a blizzard while tramping in Nelson Lakes National Park died from severe hypothermia after battling the extreme conditions on Saturday night.
The family member she was tramping with made it to Angelus Hut during the night to raise the alarm after they were unable to get cellphone reception.
But the 55-year-old woman spent the night exposed to the elements, battling a -16C chill and blustery 80km/h winds.
The woman had died by the time the Nelson Marlborough Rescue Helicopter reached her at 9am yesterday. She was found in a gully on the Mt Robert Ridge.