TOKYO (REUTERS) - Japanese Finance Minister Taro Aso said on Wednesday (April 12) that a lack of clarity on why auditors did not sign off on Toshiba Corp's earnings is problematic for shareholders and financial markets.

Aso, who is also head of the country's financial regulator, said this uncertainty could cause confusion for stock and bond markets.

Aso also said he did not want investors to lose faith in Japan's financial markets simply based on Toshiba's problems.

"The problem is it is not clear why the auditors did not sign off," Aso said. "If you're a shareholder or an investor, you'd look at Toshiba's earnings and ask, 'What is this?' This could fuel speculation that Japan's auditing standards are soft or that Toshiba has problems."

Toshiba filed twice-delayed business results on Tuesday without an endorsement from its auditor and warned its very survival was in doubt, deepening a crisis stemming from problems at its US nuclear unit Westinghouse Electric Co.

The filing carried a disclaimer from auditor PricewaterhouseCoopers (PwC) Aarata that it was unable to form an opinion of the results, increasing the likelihood that the Tokyo Stock Exchange will delist Toshiba.

The move puts the stock exchange centre-stage as it weighs the pros and cons of forcing Toshiba to delist.

Failing to act tough with Toshiba would bring into question authorities' credibility in maintaining standards for investors, but a delisting would complicate the crisis at Toshiba, increasing its financing costs and exposing it to further lawsuits from angry shareholders.

Accountants have been questioning the numbers at Westinghouse, where massive cost overruns at four nuclear reactors under construction in the Southeastern United States have forced Toshiba to estimate a US$9 billion annual net loss.