The Taupo District Mayor says he is outraged over the dumping of thousands of tyres near the edge of Lake Taupo.
Up to 7000 tyres have been dumped on farmland two kilometres from the lake front.
Mayor David Trewavas said he believed a company was contracted by the Hamilton City Council to get rid of the tyres after a recycling project that was going to use them was postponed.
Mr Trewavas said the tyres would pose a huge risk to the environment if they caught on fire.
"[Just] one tyre needs to catch on fire. The only way you can put the fire out is by way of a foam application and that is disastrous for waterways," he said.
"[That] into the groundwater and, you know, seepage into the lake would be absolutely disastrous."
He said a huge amount of work had already been done to keep the lake clean.
"We've spent millions of dollars cleaning this lake up over the last 10 years. The whole of New Zealand has contributed to that and there, these particular items of product are dumped right next door to it. It's just an outrage."
The mayor said he was talking to the Waikato Regional Council to find out how long the tyres would stay.