THE World Heritage-listed Kakadu National Park will be expanded to include thousands of hectares of ecologically sensitive land that has uranium worth billions of dollars.

Aboriginal traditional owner Jeffrey Lee has offered the land to the federal government so it can become part of Kakadu, where he works as a ranger.

Djok Clan leader Jeffrey Lee, the sole custodian of the area known as Koongarra, has generously donated his ancestral lands to the nation to become part of Kakadu National Park, despite containing sizable reserves of Uranium.

Mr Lee, the sole member of the Djok clan and senior custodian of the land known as Koongarra, could have become one of Australia's richest men if he had allowed the French energy giant Areva to extract 14,000 tonnes of uranium from its mineral lease in the area.

Mr Lee is an extremely shy and humble man who shuns publicity. "I'm not interested in money. I've got a job. I can buy tucker; I can go fishing and hunting. That's all that matters to me," he told The Age in a rare interview in 2007.