Bruce Cameron of the Otira Hotel said he had called emergency services after being alerted to the incident by people from the woman's party.
"Two trampers came running into our hotel and wanted to ring 111, so we spoke to emergency services and organised the ambulance and tried to get a helicopter," he said.
"They said two doctors were up there tramping as well and they were doing CPR on her."
The hotel was "just down the road" from where the woman had drowned, he said.
Hotel staff had also called emergency services after a bus full of tourists collided with a van in the Otira Gorge on New Year's Eve, he said.
Meanwhile, a 54-year-old Canterbury man Eric Jacomb was believed to have fallen to his death yesterday in the Mawson Glacier, near the headwaters of the Whateroa River. His body was recovered by members of the South Westland Alpine Cliff Rescue team this morning.
Mr Jacomb was one of a party of five people tramping in the area, police said. He was separated from his companions yesterday and was supposed to meet them later in the day at the Top Butler Hut.
His friends became concerned when the man failed to arrive and used their hired mountain radio to raise the alarm around 6.30 last night.
Sergeant Sean Judd of West Coast Police search and rescue said said weather conditions were such that searchers were unable to get into the area last night. The Alpine Cliff Rescue Team flew in early this morning.
"The team sighted a body at the base of a bluff. It appears the man has slipped and tragically fallen to his death."
The victim has been flown to Fox Glacier and the rest of the party were flown to Franz Josef.