Rescue teams are extremely concerned for a British man who failed to return home from a tramp in the Tararua Ranges.
The 47-year-old was scheduled to finish his five day tramp, ending at Mt Holdsworth near Masterton on Saturday, but he never showed up.
The man is from the UK, but resides in Wellington, according to police.
He entered the ranges from Levin on Tuesday, and was last heard from on Thursday
A team of around 50 people have been searching by land and air since Sunday, trying to locate the man.
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Police, New Zealand Defence Force, and LandSAR are continuing the search on Tuesday.
Conditions on the ranges are challenging with strong winds buffeting helicopters and freezing wind chill making land searches difficult.
"The Tararua Ranges are proving a challenging environment as they often are. They are an area that needs to be respected as they are - a true alpine environment," search and rescue officer Sergeant Anthony Harmer told Newshub on Tuesday.
"Cloud levels are coming down, river levels are coming up. Wind is peaking at 120 kilometres at various points along the ranges which proves very difficult," said Harmer.
Metservice meteorologist Stephen Glassey says those conditions are not looking like they will improve.
"Tomorrow, that rain is going to get heavier and more persistent, and we're expecting rain to turn to snow above 800 metres. It's also going to get very cold, probably around -13 degrees."
Harmer says the situation is serious, but survivable.
"If our lost party has made the right decisions, and has the right equipment, this is a survivable event."
On Tuesday there were 15 teams out searching for the man by land and air. Harmer says they don't intend to give up.
"We'll search until we make that decision that it's not appropriate to be searching."