WASHINGTON (AFP) - Big brother is watching - sales of George Orwell's dystopian novel 1984 have skyrocketed in the wake of revelations of US government surveillance.

The centennial edition of the novel surged 7,005 percent on Amazon, according to the online retailer's Mover and Shakers in Books page that monitors biggest gainers in sales rank compared to 24 hours ago.

"Only 8 left in stock (more on the way)," potential buyers are advised when clicking on the novel's icon.

A hardback encompassing both 1984 and Orwell's Animal Farm jumped 314 percent.

A series of high-profile leaks in the past several days have revealed how US intelligence workers trawl through phone records and Internet traffic looking for possible terror threats.

President Barack Obama says such surveillance has helped to keep Americans safe but civil liberties advocates have cried foul.