Olympus has defended paying $687m to financial advisers but refused to comment on its former CEO’s claims that the cash was channelled to “unknown parties in the Cayman Islands”.

Asked why Olympus paid such a high fee in relation to its buy-out of medical equipment firm Gyrus in 2008, Olympus’s Tokyo spokesman Ayako Nagami told Amateur Photographer (AP) this morning: “The amount paid to the adviser has been approved by a third-party firm.”

Yesterday, ousted CEO Michael Woodford repeated his claims of financial wrongdoing after Olympus admitted it had paid advisers $687m – an amount Woodford questioned with Olympus management before he was fired.

The fee represents around 35% of the entire value of the $2 billion Gyrus takeover.

Woodford claims a 1-2% fee would be the normal payment for such financial advice.

In an interview with the BBC, Woodford said Olympus paid the fee to ?unknown parties in the Cayman Islands’.

Responding to the accusation, Nagami told AP: “We do not have any comments for what Mr Woodford claims, other than [yesterday’s] statement.”

Woodford last night called for Olympus’s directors to be ‘held to account’ over the matter.

In an interview with Channel 4 News he added: “Until we deal with this issue the company is in a very bad and unstable position.”

In a statement released yesterday Olympus did not name the financial adviser involved in the takeover deal, referring to it only as “FA”.

The Serious Fraud Office has yet to decide whether to launch an investigation into claims made by Woodford, 51, who remains a director at the firm.

Olympus said it sacked Woodford as CEO owing to ‘major differences’ with its management team over the ‘direction and conduct of the company’s business’.

Woodford joined Olympus’s Southend-based medical subsidiary, KeyMed, in 1981.