Police believe there is little hope an elderly possum hunter missing in dense Canterbury bush since Wednesday will be found alive.
Allan Hill, 83, went into the Ashley Gorge and was not prepared for an overnight stay. Conditions in the rugged terrain have been cold and wet since.
Mr Hill has been trapping possums for more than 50 years and knows the area well.
A police spokesperson says small clues have been uncovered during the search but would not say what they are.
Search co-ordinator Sergeant Tony Tully says Mr Hill has a medical condition and may have had a medical misadventure or a fall.
Forty-two people from Canterbury, the West Coast and Marlborough are continuing to scour the area with the help of an Air Force helicopter and dogs.
The search will continue on Monday night and at first light on Tuesday.
Mr Hill's wife visited the area on Monday.