"He put on a life vest and swam out to the man - but by the time he got to him he was unconscious," the worker said.
Both the whitebaiter, who was wearing a life jacket, and his rescuer were then pulled in to shore.
The man may have been in the water for about half an hour before he was brought into shore, she said.
Emergency services worked to resuscitate the whitebaiter for over 40 minutes, but were unsuccessful. He was pronounced dead at the scene.
The worker said those involved in the rescue attempt had been "extremely brave", as the water was "dangerous and known for drownings".
There had been one other drowning since she had been working at the hotel, she said.
"It's obviously something that is a danger, but it is not a common occurrence."
She said the man was a regular local whitebaiter who was staying at the campground.
Wairarapa police Senior Sergeant Mike Sutton said a "pretty brave effort was made by the people down there" to pull the man from the water and resuscitate him.