Speaking at an event in Berne, Mr Hildebrand is quoted as having said: “"The idea of a merger between UBS and Credit Suisse has not yet been introduced as a concept."

According to the news service, Mr Hildebrand expressed his conviction that the two banks could continue to compete internationally, despite the recent weakening of the strict banking secrecy for which Switzerland is famed.

He went on to caution that the banks’ business models “should not be built on bank secrecy alone,” the report said.

Amid the credit crisis, UBS was forced to make bigger write-downs than any other European bank, leading it to accept SFr6 billion ($5.2 billion) in government aid last year. Credit Suisse declined government assistance.

UBS has written down more than $49 billion since mid-2007. It was recently reported by Swiss newspaper Sonntag, citing people familiar with the matter, that the bank would write down at least another $2 billion on illiquid assets, including asset categories so far not much in the spotlight such as Credit Linked Obligations.

The bank revised up its 2008 net loss to SFr20.9 billion ($18.2 billion) on 11 March and said its near-term outlook was extremely cautious, warning that its balance sheet remained exposed to illiquid and volatile markets.