Key Points:

The brother of missing Israeli tramper Liat Okin is confident she is still alive.

Ms Okin, 35, has not been seen since failing to return from tramping the Routeburn Track through the Mt Aspiring and Fiordland National Parks on March 25.

Itamar Tas, 26, who flew to Queenstown from Israel on Friday, was accompanied by his closest friend, Joe Kariv, and one of Israel's most high-profile professional mountain guides, Magnus Hilik, operations manager of Israel's search and rescue team.