From the 1960s, the area was quarried which posed a major threat to the tiny frogs that can easily be crushed by walkers, horses or passing vehicles.
Local Forest and Bird branches were blockaded from the area and accused of trespassing by the quarry owner.
Al Fleming, Forest and Bird's central North Island conservation manager, had the air in his vehicle's tyres released on one visit.
"Members from both Te Puke and Tauranga have 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," said Fleming.
Hochstetter's frogs are as unique to New Zealand as our iconic kiwi and kakapo.
They belong to an ancient genus, which split off from other frog species around the time of the dinosaurs.
The frogs exhibit many strange and primitive traits such as being voiceless, lacking external ears, and hatching as tiny froglets instead of tadpoles.
In 2009, the quarrying stopped leaving the land unstable.
Despite these hardships the population of frogs has persisted.
"The frogs now have a chance and the new sanctuary land status give DOC and the community an opportunity to restore the frogs' habitat, protect them from predators, and ensure that the frogs' recovery and protection is a priority," Fleming said.
"This is a story of persistence and determination. These special animals have been around for a very long time, and Forest and Bird members are proud to have played a role in guaranteeing them a future."