The three-year-old sable-coloured german shepherd had been working with a search and rescue team on a day-long exercise when he became parted from his handler in the Totara Creek to Red Creek area at Mt Holdsworth on Sunday afternoon.
"He was working with the team down a really hard spur and it's unknown how, but he just got separated. The terrain was rough and visibility was bad."
Mr Davidson said a team of eight volunteers including Mr Wakefield and two other dog handlers were today scouring the area where Thames was last sighted.
Two more dog handlers were patrolling roads near the popular tramping area and Senior Constable Tony Matheson, head of Wairarapa LandSAR, will camp in the mountains tonight in hopes of Thames finding his way to him.
Searchers were relying on the dog being attracted to their scent and despite the "outside chance" the animal had been injured in a fall, Mr Davidson remained confident Thames could still walk out hungry but otherwise healthy in seven days' time or more.
He said the threat of heavy weather hitting the area tomorrow night could mean the search will be scaled down or called off tomorrow morning.
"We could sustain the search for a while yet but it depends on what's sensible and what's realistic. Tomorrow is just not realistic, not with the weather looking like it is."