"Of course I will be available to the business examination committee and contribute to clearing up open questions," Mr Ospel was quoted as saying. The newspaper report was translated by Reuters.

"I have nothing to hide," Mr Ospel said.

UBS said in December it would not sue its former bosses.

The former management of the banking and wealth management giant face criticism that they ran the firm as it accumulated massive losses from the US sub-prime mortgage meltdown, as well as allowing the bank to get embroiled in a tax evasion case in the US.

Mr Ospel said he had yet to be invited to speak to the parliamentary committee examining the government's action on UBS.

Mr Ospel and other ex-board members agreed to return SFr33 million ($30.7 million) in payments from the bank. The bank said the return of money was not an admission of guilt on its part.

Meanwhioe, the right-wing Swiss SVP party said yesterday it opposes retroactive parliamentary approval of a deal between UBS and the US on disclosure of secret bank accounts held by US clients of the bank.

Last August, UBS and the Swiss government agreed in August to disclose details of 4,450 secret accounts that US citizens used to hide money from tax authorities.

However, a top Swiss court has ruled this year that such a transfer of data breaks Swiss banking laws. The Swiss government has called for parliamentary retroactive approval for the data transfer.

The government has not laid out an alternate strategy for what would happen if the deal were not approved by parliament, Reuters said.