Officers said the discovery was made by members of the search party just before midday on Thursday.
Police said the body found was believed to be that of Sharon, pending formal identification, after days of intensive land and air searches across harsh desert terrain.
They described the development as a devastating outcome for her family, the community and all those involved in the operation.
Sharon vanished after being put to bed at a town camp near Alice Springs on Saturday night, sparking a major search and manhunt for recently released prisoner Jefferson Lewis, who was accused of abducting her from an Old Timers camp residence.
Officers are hunting for the 47-year-old, warning his family not to help him and vowing "we're coming for you".
Scores of police officers, emergency crews, defence personnel, Aboriginal trackers and community volunteers had been scouring the area using helicopters, drones, horses, dogs and all-terrain vehicles in the hope of finding the girl alive.
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