By Takahiko Wada

TOKYO (Reuters) - Japanese lawmakers on Wednesday called for a tough regulatory response to Toshiba Corp's <6502.T> second postponement of its annual results over accounting woes, saying the scandal could erode foreign investor confidence.

Regulators are likely to penalize the laptop-to-nuclear power conglomerate with a fine after an independent probe found that the company had overstated past results by $1.2 billion over several years, sources familiar with matter have said.

Japan's regulators are, however, often perceived as softer than Western counterparts when punishing corporate misdeeds."The scandal is a severe problem that could lead to a loss of credibility from foreign investors", Masahiko Shibayama, head of the Liberal Democratic Party's treasury and finance division, told reporters after a meeting of lawmakers and regulators.

The Tokyo Stock Exchange would consider putting Toshiba's shares on a watchlist for possible delisting if there were further delays in reporting results, Shibayama quoted a bourse official as saying in the meeting.

Forced delistings are, however, rare. Kazuhiko Toyama, who advised the government on new corporate governance guidelines that seek to improve shareholder returns, said a delisting would not be the answer.

"The exchange should not delist Toshiba because the direct victims of a delisting would be the shareholders and not the company," he told a news briefing on corporate governance.

The accounting scandal is Japan's biggest since 2011 when camera and medical device maker Olympus Corp <7733.T> was found to be involved in a $1.7 billion scheme to conceal two decades of investment losses. Olympus was subsequently fined 700 million yen ($5.8 million) and some former executives were handed suspended jail sentences.

Toshiba put off plans to announce annual results on Monday, citing newfound accounting errors, receiving a government extension to submit them by Sept. 7. It said the new errors were not huge.

Shares in the sprawling conglomerate have tumbled more than 30 percent since it disclosed in April a probe into its past book-keeping practices, giving it a current market value of some $12.3 billion.

(Reporting by Takahiko Wada; Additional reporting by Makiko Yamazaki; Writing by Ritsuko Ando; Editing by Edwina Gibbs)