NSW National Parks and Wildlife Service have started dropping food for endangered Brush-tailed Rock-wallabies across the state, as over 1 billion of Australia's unique wildlife are estimated to have perished in the bushfires.

Over the past week, tonnes of mostly sweet potatoes and carrots have been dropped over Capertee and Wolgan valleys, Yengo National Park, Kangaroo Valley, Jenolan, Oxley Wild Rivers and Curracubundi national parks.

Endangered Brush-tailed Rock-wallabies in fire-affected areas have received a food drop of carrots and sweet potato. Credit:NPWS NSW

NSW Environment Minister Matthew Kean said the food drops form part of a state-wide scheme addressing post-fire wildlife recovery.

"The provision of supplementary food is one of the key strategies we are deploying to promote the survival and recovery of endangered species like the Brush-tailed Rock-wallaby," Mr Kean said.