A "fatberg" of wet wipes and congealed fat has caused wastewater to overflow from a manhole into Lake Taupo last night, closing a section of the foreshore as unsafe.
Taupo District Council said the spill occurred at the end of Hawai St, Richmond Heights, and a temporary health warning is in place not to swim in the area until water testing results come in tomorrow.
Council operational services manager Kevin Strongman said waste contractors were onsite quickly after the alarm was raised at about 9pm last night.
"When wastewater escapes from a manhole, the resulting spill enters the stormwater system through nearby grates and because of gravity, it ends up in the lake," Mr Strongman said.
"Clearly we are really disappointed by this situation and find it just as frustrating as the community.
"We've invested around $100,000 a year on CCTV assessments of the system, and another $50,000 a year in high-pressure water cleaning to try and stop spills from happening."
A sucker truck was used to try and clean up as much of the spill as possible where it exited the stormwater outlet.
Taupo District Council said the waste water leak has not affected the Two Mile Bay Sailing Centre.
"Our teams are constantly working to monitor the system and improve it, but we really need the public to play their part. Wet wipes and nappy liners should not end up in the wastewater system – they should be disposed of in the rubbish," Mr Strongman said.