Police had deployed 10 teams of three people into the Hope Arm area in the ongoing search for the woman known as Tina, Senior Sergeant Ben Butterfield, of Southern District Police, said.
The teams consisted of search and rescue volunteers from Te Anau, Invercargill, Gore and Dunedin and two search dogs from Dunedin.
Southern Lakes Helicopter were supporting the ground search effort, Snr Sgt Butterfield said.
The woman, believed to be a 25-year-old German female, has long auburn hair and is of medium build.
She was dropped by water taxi at 11am on Thursday on the western banks of the Waiau River and it is believed she intended to walk to the Hope Arm hut and return.
She was last seen wearing dark clothing and a small day pack.
She failed to meet her arranged water taxi at 6.30pm. Police were notified at 8:30pm and searchers were deployed.
Police inquiries to ascertain the identity of Tina were continuing, he said.
Anyone with information should contact their nearest police station or call Te Anau police station on 03 249 7600.
