The deal could be completed as soon as next month, sources told the Japanese news agency.
The move comes after the outspoken governor of Tokyo, Shintaro Ishihara, made a similar offer to buy the Senkaku Islands from their private owner earlier this year. The islands, known as Diaoyu in China, have been the center of territorial disputes between China and Japan for decades, and it's thought the sale could strengthen the Japanese government's hold on them.
China has laughed off threats to buy the uninhabited islands before. "No one will ever be permitted to buy and sell China's sacred territory," Foreign Ministry spokesman Liu Weimin said earlier this year.