One person has died after four people have been swept down the Waikato River, north of Taupo.
A staffer said the group were swimmers "in bikinis and togs", in their early 20s.
The young woman swept to her death when floodgates opened on the Waikato River knew missing 21-year-old Carrisa Avison.
Police last night named 21-year-old Rachael De Jong as the victim of Monday's river tragedy.
A week before her tragic death De Jong shared a link to a news article about Avison, who disappeared on January 26, on her Facebook page.
"Please come home," De Jong wrote.
De Jong, an Auckland University of Technology student with an infectious smile that could "cheer anyone up", was swimming with friends in the river when the Aratiatia Dam floodgates opened.
"Yesterday I lost one of the most important people in my life, my wonderful sister. Not only was she an inspiration to us all, she was my best friend, and the most perfect sister I could've ever asked for.
"I can't even begin to describe how much I'm going to miss you, and how incredibly unfair it is that you have been taken far, far too soon.
"You never spoke a bad word of anyone, and you had such an infectious smile that could cheer anyone up. I love you so much Rachael, rest easy."
With the post was a black and white image of him cuddling her.
Other tributes starting to appear on social media also reflected a friendly and happy young woman who would be missed by many.
One person described her as "the kindest and most gentle soul".
"Rest in peace, sweetie, you'll always be remembered for the kindness and happiness you brought."
Taupo Sergeant Shane McNally said he understood the group had been visiting Taupo for the weekend.
They had met at the Flochella music festival on Lake Taupo the day before and then decided to stop at the dam for a swim the next day. Some of them had swum there in the past.
He said despite the four water releases a day in summer and warning signs, some people still swam in the pools that were left behind after the rapids had stopped flowing.
"But when the sirens sound, you get out," he said.
"It's unknown why they didn't."
people gather at drowning scene.
The dam's gates open four times a day in summer so tourists can watch the rapids from a viewing platform. The water is calm when the gates are closed but quickly rises when they open.
The section of the river near the dam is fenced off to prevent people swimming.
Signs alerting people to the danger are also in place on the bank and sirens are let off before the gates open.
The town's mayor, David Trewavas, told the Herald he had spoken to the dam's operator Mercury Energy, which is reviewing its safety procedures after the drowning, and it appeared not much more could have been done to prevent the death.
"It's an absolute tragedy what's happened but it sounds like the systems were in place and the signs were up and the siren went off, so it's one of those unfortunate things."
Mercury Energy chief executive Fraser Whineray confirmed yesterday the sirens were working when the drowning happened.
The death follows a close call in the same spot in 2009 when two women were swept down the river after the floodgates opened and they had to be plucked to safety by kayakers.
