An Australian bushwalker who tumbled down a waterfall, snapping his leg in two, told Wednesday how he managed to crawl for two arduous days through scrub and forest to safety.

Neil Parker, 54, said his planned three-hour hike in northwest of Brisbane went horribly wrong Sunday when he slipped six meters down the waterfall, fracturing his leg and wrist.

The experienced hiker said the entire bottom half of his leg was hanging loose thanks to a "clean snap in half."

He immediately tried to phone for help, but after dropping his mobile "into the drink," he started crawling back to a clearing where he believed he would have a better chance of being rescued.

With just a "handful of nuts, a protein bar and some lollies" to sustain him, Parker began the excruciating three-kilometer journey, "scrambling and lifting, inch-by-inch" to the clearing.

Parker was eventually spotted by the helicopter and winched out on Tuesday.

AFP