Finding escaped prisoner Stephen Maddren is now like finding a needle in a haystack, police concede.
Police scaled back the search for Maddren (25) and were now only responding to sightings, Detective Sergeant Stan Leishman, of Balclutha, said yesterday.
Police still had concerns for Maddren's safety as he remained at large for a seventh night in cold and sometimes wet weather.
Read more: Escaped prisoner: Mum's emotional plea - 'Hand yourself in'
''We would be concerned if he's been out in this weather for that period of time,'' Det Sgt Leishman said.
Last Tuesday, Maddren became the first person to escape from the Otago Corrections Facility at Milburn.
Despite several reported sightings, police had nothing to substantiate the claims and were unsure of Maddren's location, Det Sgt Leishman said.
Sightings from as far away as Clinton have been reported.
Police would look at ''conducting a very thorough search'' of the forestry block near the prison to ''rule out that something had happened to him''.
Det Sgt Leishman could not confirm when such a search would take place, but was confident the area around the prison had been ''thoroughly searched'' and no ''identifiable evidence'' of Maddren had been found.
He ''implored'' Maddren to hand himself in and said: ''It's not too late''.
''We'd like to put a message out to Stephen ... to ask him to hand himself in and end this,'' he said.