Ms Okin (35) vanished while walking the Routeburn Track alone on March 26, having last been seen around the Mackenzie Hut area on March 27.
The official search was called off on April 22 when no sign of Ms Okin or any of her belongings were found, despite exhaustive searching by police, search and rescue teams, a specialist search dog and Department of Conservation rangers.
Ms Okin's brother, Itamar Tas (26), launched a private search on April 24 with a team of experienced volunteers, led by Israeli search and rescue expert Hilik Magnus, who flew in from India, scouring the track for any sign of the woman.
However, hope turned to despair at the weekend after footprints discovered last Tuesday were found not to be Ms Okin's.
The trail of footprints stretched about 40m, leading away from the track and down a difficult slope towards the Hollyford Valley, midway between the Mackenzie and Routeburn Falls huts.
Last week, Mr Tas said the prints appeared to match Ms Okin's small shoe size and the sneakers she was believed to be wearing at the time of her disappearance, although the exact shoe type was not known.
Speaking to the Otago Daily Times yesterday, Mr Tas said the search teams had not found anything which could link the prints to his sister, who has not been seen for 46 days.
"Basically, we feel we've really exhausted the area and the possibilities of it there.
"I'm not sure what we're going to do.
"I'm going to stay here until Saturday anyway - I need to check with my family [in Israel] and see what they think.
"Nothing is very certain at the moment."
