The 35-year-old, a highly educated divorcee with a stint in the Israeli army behind her, left home for a six-month trip to Thailand, Australia and New Zealand after deciding to "fulfil what she hadn't done before'', her brother, Itamar Tas says.
Mr Tas(26) - who arrived in Queenstown from Israel on April 11 - is waiting desperately for news in a Queenstown hotel room, as the hunt for his missing sister drags into its third week.
Ms Okin vanished on the Routeburn Track and there has been no trace of her since she was last seen, preparing to leave Mackenzie hut on the morning of March 26. Her passport and travellers' cheques, left for safekeeping at a friend's house in Queenstown, have not been collected, and her regular phone calls to Israel have ceased.
The air and ground search of "nightmare'' terrain around the track, involving police and a specialist search dog, search and rescue squad members and Department of Conservation rangers, has been continuing since April 7, but has found nothing.
Ms Okin was believed to have been tackling the arduous section of track between Mackenzie and Routeburn Falls huts, which winds through thick bush and over an alpine saddle overlooking the Hollyford Valley, when she disappeared.
Searchers fear she might have fallen or taken a wrong turn and lost her way.
Mr Tas, speaking to the Otago Daily Times from his hotel room, said his sister was an active woman who enjoyed the outdoors, but had not tackled anything quite like the rugged Routeburn Track before.
"Since she was a child, she used to always play outside and climb on trees and build stuff on the trees. She's an outdoors person.''
Ms Okin was born in the Israeli city of Hrehovot in 1972, and moved with her parents to the small, peaceful country village of Netiv Haasaa, where she grew up in "a very beautiful place'', Mr Tas said.
The village was just a short distance north of the troubled Gaza Strip and it was there, as an 18-year-old, that Ms Okin was posted to serve her two years' compulsory military service, after completing her schooling, he said. She worked as a communications officer at a military base, returning home on weekends.
After completing her military service, Ms Okin travelled to the United States to visit friends and study. She completed a bachelor of arts degree in behavioural science at a New Jersey university, met and married David Okin, a Jewish American living in New York.
After Ms Okin completed her studies in 1995, the couple decided to go to Israel, but her husband found it difficult to acclimatise.
"For David, it was very difficult to stay in Israel without knowing the language,'' Mr Tas said.
They persevered, but eventually decided to return to the United States, after Ms Okin had completed a master's degree in social work. This time it was Ms Okin's turn to feel homesick and the couple eventually divorced.
"She never liked to live out of Israel. When she married, she told her husband she would like to move. It made problems and they decided to get divorced,'' Mr Tas said.
She returned to Israel alone and threw herself into her work with the young, the poor and the mentally disturbed, Mr Tas said.
However, last year she set her sights overseas and decided to travel once again, Mr Tas said.
"She decided to fulfil what she hadn't done before. She decided to come to New Zealand and Australia because it's considered a safer place.''
She set off in early November, travelling first to Thailand for a three-week stopover, before continuing on to Australia, where she spent two months.
She arrived in New Zealand at the end of February and had been travelling the country.
It was believed Ms Okin had struck up friendships in Queenstown in the days before she decided to tackle the Routeburn Track, including two fellow Israeli girls who had planned to accompany her on her latest adventure.
The plans fell through and Ms Okin went alone to start the Routeburn Track at the Divide, near Milford Sound, leaving her passport and other property in Queenstown.
The last person known to have seen her, a fellow tramper who helped her with her pack on the morning of March 26, has since told police she was carrying more food than was first thought.
Well equipped for the day ahead, she carried limited experience when she set off down the track that morning.
Now, all her brother can do is wait in Queenstown and make his nightly phone call back to Israel,with the sombre news - that there is no news.
"I don't have a lot of sleep,'' he said.
"It's very frustrating and I feel very helpless.''
