One of the people behind the hit television show Lost is reviewing search and rescue operations in the hunt for Dunedin man David Palmer, who is still missing in the Dingle Burn area.
Mr Palmer's friends have also helped by supplying searchers with photographs from previous trips he made to the area and a bootprint found near his car to aid in identifying any tracks.
That has widened the search area.
An Otago University health science library assistant, Mr Palmer, 53, has been missing since Saturday when he set out on what was expected to be a three or four-hour tramp.
Last night, police confirmed searchers had found "items of interest" which had yet to be officially linked to Mr Palmer.
About 35 people are expected to continue searching the Ahuriri Valley Conservation Park today in specific areas including Mt Gladwish, a 1861m peak, as well as steep gorges with waterways, Search and Rescue incident controller Senior Sergeant Brian Benn said last night.
Search and Rescue Institute New Zealand development manager Ross Gordon, a key consultant on the TV show Lost, was one of three independent experts brought in to review search proceedings yesterday.
Mr Palmer's family members were also shown what was being done at the Birchfield operation base.
Mr Benn said the involvement of independent reviewers was best practice.
"Largely it is just to get a fresh perspective and a fresh set of eyes. Most searches are solved through initial searches and reflex tasking, but because we have a very large area and difficult terrain we have asked for an outside perspective," he said.
All independent reviewers had international search and rescue experience and were well respected nationally and abroad.
Mr Benn said searchers had a good picture of Mr Palmer's possible plans, after friends and family accessed his computer to send photographs taken on previous trips.
The photographs prompted searchers to consider areas north and south of the Dingle Burn Saddle.
"We know he is a landscape photographer and likes to go to high points of the valley to get pictures. That helps us decide a lot about his behaviour," Mr Benn said.
"It was a beautiful day when he went missing, it was the night of the big moon. All those little pieces of information go into the mix when creating a person profile, which might help about the sort of behaviour he might do outdoors," he said.
A diary found in Mr Palmer's car revealed him as a positive individual with a desire to climb Mount Kilimanjaro, Mr Benn said.
Police and SAR advisers believed Mr Palmer was within the 200 sq km search area.
Despite recent snow falling up to 10cm thick, Mr Benn said the situation was "very survivable".
Low cloud and rain lifted late yesterday, allowing an Iroquois helicopter to fly.
University of Otago librarian Howard Amos said Mr Palmer, who had diabetes, was well known and respected among staff.
"Our thoughts are with his family as they await further news at this time," he said.