A former Toshiba president has been questioned by Japan's markets watchdog and may face criminal charges over his alleged involvement in a falsified earnings scandal, reports said Saturday.

The company has been roiled by a profit-padding scandal, in which bosses for years systematically pushed their subordinates to cover-up weak financial figures.

Hisao Tanaka was quizzed by the Securities and Exchange Surveillance Commission (SESC), according to Japan's public broadcaster NHK and other news reports.

The watchdog suspects Tanaka and two other former Toshiba presidents were aware of falsified profits in its personal computer section but did not step in, NHK said, quoting unnamed sources close to the case.

Tanaka is believed to have denied any wrongdoing, NHK said, adding that the SESC is examining whether to seek criminal prosecution of the three on suspicion of falsifying financial reports in violation of the Financial Instruments and Exchange Act.

SESC could not be reached Saturday for comment.

Toshiba -- a vast conglomerate that makes everything from rice cookers to nuclear plants -- is expecting a huge loss of about 710 billion yen ($6.4 billion) for the year to March with sagging global demand also contributing to its financial woes.

The embattled firm said Friday that its US units are cooperating with American authorities over alleged accounting irregularities.

In a statement released on Friday, Toshiba said that "several" of its US subsidiaries have been asked for information by the US Department of Justice and Securities and Exchange Commission.