Dozens of rat and stoat traps set to protect kiwi on the banks of Lake Waikaremoana were found broken, burned and shot with bullets recently.
The traps, set by volunteer charity the Lake Waikaremoana Hapu Restoration Trust, were found by trust president Robert Waiwai on the Whareama Peninsula last week.
Liaison Lisa Waiwai said it was heartbreaking that the work of so many volunteers had been destroyed.
"It's sad, it sort of breaks your heart," she said. "We take it personally because we put so much time and energy into the bigger picture for other people to come and enjoy ... and then people come and do something like this."
Mr Waiwai had brought 18 of the damaged traps back from the remote area, but it was hard to know how many were destroyed by fire.