TOKYO (REUTERS) - Toshiba Corp, which is expected to mark down past profits due to an accounting scandal, is considering selling assets including part of its stake in Westinghouse Electric, sources with knowledge of the matter said on Thursday.

The Nikkei business daily, which first reported the news, said the Japanese industrial conglomerate plans to generate about 200 billion yen (S$2.24 billion) through the sales.

A Toshiba spokesman said the company had already been considering lowering its 87 per cent stake in Westinghouse Electric and that this had nothing to do with its accounting investigation.

"We've been looking for a partner for some time. Our position hasn't changed," spokesman Hirokazu Tsukimoto said, adding that Toshiba wanted to maintain a majority stake in the US-based nuclear power company.

He declined to comment on whether the company was in talks with any potential investors.

Shares of Toshiba were down 5 per cent on Thursday morning in Tokyo. The stock has lost more than a quarter of its value since it first disclosed in early April that it was investigating past accounting practices in infrastructure and construction.

The Nikkei said accounting irregularities had been found in all of Toshiba's main segments, including semiconductors. It also said Vice Chairman Norio Sasaki, who served as president between 2009 and 2013, would likely step down from the board of directors.

A third-party investigation is expected to take until mid-July, Toshiba has said.

On Wednesday, sources familiar with the discussions said Toshiba has talked with banks about a credit line worth up to 600 billion yen to secure funding in case the investigation hurts its creditworthiness.

Toshiba may need to mark down past earnings by over 100 billion yen due to past accounting errors, another source has told Reuters.