Swimmers continue to risk their lives in a fatal stretch of water below the Aratiatia Dam despite numerous safety barriers and warning signs.
Today, for the second day in a row, Mercury has been forced to cancel tourist spills at the rapids, north of Lake Taupō, due to safety concerns.
Mercury hydro general manager Phil Gibson said it was frustrating, with lives being put at risk and undue pressure being put Aratiatia hydro station staff who manage the spill.
"We acknowledge that the tourist spill is a fantastic tourist attraction for the region," he said.
"There are a number of businesses that benefit from it, as well as thousands of people each summer and through the year who enjoy witnessing the power of the spills from safe vantage points.
"When people ignore signage and head into the area of the rapids, no matter the time of the day, they are putting themselves in danger but also impacting the lives of others. It is time for that to stop, or Mercury will have to reconsider whether spills can continue safely."
Tourist spills have been a feature at Aratiatia since the station was completed by the Government in 1964.
Spills can occur for both operational and tourism purposes. Operational spills can be planned or unplanned and can occur at any time. Water from the Waikato River can also flow down the Aratiatia Rapids at any time and without warning.
Unexpected releases of water meant it was dangerous to be in the area of the rapids at any time as levels could rise suddenly and dramatically.
In 2017, 21-year-old Rachael de Jong was swept to her death after swimming with friends about 200m below the Aratiatia Dam when the floodgates opened.
Within minutes, the tranquil water turned into a torrent.
Horrified tourists could do nothing but watch as the physiotherapy student and her friends were trapped on a rock and dived to safety, one by one, as the water rose around them.
Although de Jong scrambled to safety, she put herself back in harm's way to help others and was swept downstream.
New safety barriers and warning signs were installed after de Jong's death but people did not appear to be taking them seriously.
Gibson said that on Monday, a 4WD carrying a number of people parked and the group deliberately avoided signage and barriers to enter the area.
However, they were seen and the 10am scheduled spill was stopped and police called.
The 12pm spill was also halted while an investigation was completed.
Today, the 10am spill was cancelled in similar circumstances. The 12pm spill was also stopped and a review held before starting again at 2pm.
"We are asking for community help with this," Gibson said.
"If people hear of others planning such activity, or they witness people in areas beyond the safe zones for viewing, they need to call out that behaviour and help stop it.
"Those people who ignore the warnings risk not only their lives, but ruining enjoyment of the spectacle for others as we could be forced to halt these spills for longer periods or even indefinitely.
"Safety has to be, and is, paramount. It is unacceptable that our station employees are put in the position of having to make calls about releasing water or not, sometimes with just minutes' notice, while people are playing around and even trying to avoid being seen."
Mercury, as part of its consents for operating the Aratiatia hydro station, manages controlled spills through the area of the rapids at 10am, 12pm and 2pm, as well as 4pm in the summer.