Japan's Toshiba is in talks with three parties about selling a stake of up to 16 percent in US nuclear power plant builder Westinghouse Electric, a report said Thursday.

Toshiba, which currently owns 67 percent of Westinghouse, still intends to keep a controlling share, the Japanese firm's president Norio Sasaki told Dow Jones Newswires.

The three parties "have made very good offers", Sasaki said, adding they include companies outside the United States.

Sasaki also said another 20 percent in Westinghouse which Shaw Group currently owns -- but which Toshiba is set to acquire in January under the terms of a put option-- may be purchased by Chicago Bridge & Iron Co.

However, Toshiba has received proposals from two other companies to buy the stake, he added.

Chicago Bridge is in the process of purchasing Shaw after its shareholders overwhelmingly approved the $3.04 billion acquisition earlier this month.