Scandal-hit Olympus is suing some 20 current and former executives for damages over a massive investment loss cover up at the Japanese firm, reports said Monday.

The law suits filed Sunday named ex-president Tsuyoshi Kikukawa, pegged as playing a major role in the embarrassing affair, and his successor Shuichi Takayama, the Yomiuri Shimbun said, citing sources close the case.

Earlier reports said Takayama will step down this month after an in-house panel probing the cover up named him among those responsible for the scandal.

The embattled camera and medical equipment maker's former vice president Hisashi Mori and former auditor Hideo Yamada were also believed to be among those sued, the Nikkei business daily said on Monday without citing sources.

The combined damage claims could total hundreds of millions of dollars against more than 10 Olympus officers, the Nikkei said on Sunday before the company announced it was considering lodging law suits.

Earlier reports have said the damages claim could top $1.0 billion.

Olympus officials were not immediately available to comment on Monday, which was a public holiday in Japan.

The Sunday statement came after an in-house panel investigated the responsibility of Olympus board members in a scandal that rocked the 92-year-old firm and undermined public trust in Japanese corporate governance.

"Upon receiving the report (on Saturday), we are currently discussing filing law suits against the current and former board members," it said.

Olympus said it would disclose the report's findings and discuss the company's future plans on Tuesday.

The three-lawyer panel was tasked with investigating the exact responsibility of the Olympus board members in the scandal.

A separate committee of former judges and outside experts, commissioned by the company, condemned Olympus' top management as "rotten."

The company has admitted that a small group of top executives hid at least 134.9 billion yen ($1.75 billion) in losses from bad investments in the 1990s.

The scandal came to light after its first foreign president Michael Woodford exposed the matter last year by talking to the international media and authorities, as Olympus' old guard quickly sacked him from the top post.

Despite months of campaigning to clean up the Olympus board, Woodford has given up his efforts to return to and lead the company due to lack of support from major Japanese institutional shareholders.