Surveys of koalas in Kosciuszko National Park indicate populations exist in other unexplored regions, including Namadgi, research has found.
The scantly seen Kosciuszko koala has been detected in about 100 acoustic recordings and spotlight surveys conducted in November and February.
NSW Environment Minister Ben Franklin said before the most recent surveys, just 16 sightings had been recorded in the park in the past 80 years.
Australian National University Professor David Lindenmayer took part in the research, conducted in partnership with NSW Parks and Wildlife Service.
Professor Lindenmayer said it was "very likely" remote areas of Namadgi National Park also contained koala populations.
"We know in the past there's been koala populations on the boundary between the Brindabella National Park, on the border between the ACT and NSW. It's pretty likely there'll be koalas in some of these other places," he said.
Park rangers and researchers detected koalas in just under 20 sites in Kosciuszko, primarily in the Byadbo Wilderness Area, south of Jindabyne towards the Victorian border.
Professor Lindenmayer said the sightings were mostly across an area of about 20km by 25km, while droppings had been located closer to Jindabyne.
He said the majority of work done previously had been in high alpine areas, despite the park being 690,000 hectares and including montane forests, tablelands and woodlands.
"There's a camera record of animals at Blowering and Tumut, so they're likely to be in low densities across some non-trivial parts of the park - which is wonderful," he said.
He said the best way to record them was when the males were bellowing during breeding season.
"They make this amazing call. It sounds a little bit like a pig snorting," Prof Lindenmayer said.
Prof Lindenmayer said further inland towards Tumut there were remote areas that would be difficult to access and offered hope for additional populations.
"We won't know until we get into them and start to have a look," he said.
NSW has a $193 million strategy to preserve habitat, with the target of doubling the state's koala population by 2050.
The state has also acquired land it plans to turn into safehavens for wildlife at risk of endangerment or extinction.
The ANU study has received backing to continue surveying koalas in additional parts of the park for the next 12 months.
The Australian native was listed as endangered in the ACT, NSW and Queensland in February, following a recommendation from animal welfare groups in 2020.
Koalas were thought to only exist in the wild in Namadgi as visitors from their permanent habitat in NSW.
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Prof Lindenmayer said the areas they had located koalas in Kosciuszko were so remote that threats to their survival were minimal.
He said there was potential for the national parks to provide a refuge as the climate changed.
"One of the key things about Kosciuszko and potentially Namadgi is that there are really quite steep gradients in elevation. That's important because as temperatures get hotter and hotter in south-eastern Australia, there may well be climate refuges for some of these koalas in some of these places," Prof Lindenmayer said.