The Bay of Plenty habitat of a rare native frog has been officially classed a sanctuary, ending a two-decade conservation battle.
Forest and Bird says the new status of the 400ha area of land near Te Puke will allow the population of tiny Hochstetter's frogs there to be protected and have a chance of long-term survival.
Twenty-four years ago, a volunteer on a Forest and Bird walk found the first frog in the Otawa block, but the organisation was later accused of putting it there.
Forest and Bird Central North Island conservation manager Al Fleming says the area was quarried from the 1960s, posing a threat to the habitat.
He says members from the Te Puke and Tauranga branches "fought tenaciously for the welfare of this rare and beautiful frog".
"Without their combined efforts, the Otawa frog population could have been destroyed by the quarry owner years ago," he said.
The quarrying ended in 2009 but Mr Fleming said the land remained unstable and human disturbance was an issue.
He said the tiny frogs could easily be crushed by walkers, horses or passing vehicles.
"Despite all these hardships, the population of frogs has persisted," he said.
Hochstetter's frogs are divided into 19 genetically distinct populations.
The Otawa population is believed to be the smallest - about 200 individuals - and has been identified as critical, or one step away from extinction.