The NSW Government has announced it will open a new national park with a koala habitat in the Southern Highlands.

Couched as a win for koalas, Premier Gladys Berejiklian said the 3680-hectare park, which will be in the north of the Goulburn electorate bordering Wollondilly, will ensure that a vital koala wilderness area is preserved.

At risk: Koala habitat has been severely eroded. Credit:Karleen Minney

"The new park we’re establishing has a unique koala habitat within it," she said. "Koalas are an iconic species and we are acting to ensure their survival."

The government has purchased a 2200-hectare property from a private owner that joins the southern end of Wollondilly River Nature Reserve and the northern part of Bangadilly National Park, allowing it to establish a vital corridor for koalas.