Swiss banks have issued orders to their top executives preventing them from travelling to the US, according to a financial times report which quotes the head of an unnamed Geneva-based private bank.

The orders come amid fears that executives could be arrested and forced to reveal their banking secrets if they set foot in America.

The IRS probe into alledged tax evasion by some of UBS’s wealthiest US clients has already yielded one casualty, with a senior UBS executive taken into custody for questioning last year.

Earlier this year, Raol Weil the former head of UBS’s wealth managment arm was formally declared a fugitive by US authorities after failing to give himself up on charges that he conspired to help American clients to hide their assets.

Some Swiss banks are even forbidding travel to France and Germany, in recognition of the deteriorating relationship between Switzerland and these countries over the issue of Swiss bank secrecy, and a perceived worldwide ‘crackdown’ on offshore banking.

The Swiss Banking Association has played down these statements – it is not recommending that its members  abroad out of fear of arrest – said the group’s chairman on Thursday. Individual banks however, are free to issue their own guidelines.