Behind a high electrified fence in the state’s south-west are 9500 hectares of land that are cat- and fox-free. It means 150 animals released in the past six months, including the fluffy brush-tailed bettong or the numbat, can safely thrive and repopulate.

The property in the Mallee Cliffs National Park is one of seven feral predator-free zones where conservationists are working hard to save animals from extinction.

In the park, 60 vulnerable red-tailed phascogales were released into the wild late last year after an absence of almost 150 years. This population of tree-dwelling carnivores, which are related to the Tasmanian devil, is expected to grow to more than 1500 once established.

The phascogales were joined by 70 brush-tailed bettongs and another 20 numbats, the latter boosting a founding population established at Mallee Cliffs in 2020.

Senior ecologist guide at Australian Wild Conservancy Laurence Berry said over the last 200 years, Australia had lost over 34 mammal species – more than the rest of the world combined. He said the main drivers included predators, climate change and land clearing.

“These sorts of conservation initiatives are critical if we want to see ... these really important threatened species, that live nowhere else on earth, protected for generations,” Dr Berry said.

NSW Environment Minister James Griffin visited the feral predator-free site in the Pilliga State Conservation Area on Tuesday and said the projects, funded by the state government and managed in partnership by the National Parks and Wildlife Service, Australian Wildlife Conservancy and UNSW Wild Deserts, were vital in protecting biodiversity.

“It’s one of the most ambitious mammal rewilding programs in Australia,” he said. “Here at the Pilliga, we’ve seen the endangered bridled nail-tail wallaby population double since it was reintroduced to this now feral-free area in August 2019, from 42 to about 90 at the latest estimate, including many females with joeys in pouches.