The Federal Reserve System, the Office of the Comptroller of the Currency, the Federal Deposit Insurance Corporation and the Office of Thrift Supervision have issued a joint advisory notice calling on banks to consider the impact of a possible bird flu pandemic on business.

"A pandemic event is a potential threat to any financial institution regardless of size and location," the advisory statement says.

The document states that financial firms should have business contigency plans to deal with possible high levels of absenteeism in the event of an outbreak. Measures to control possible infection in the workplace should also be considered, including options for working at home for staff who are ill.

In January the US Financial Services Sector Coordinating Council (FSSCC) said a possible avian influenza pandemic poses a "unique threat" to the industry and called on banks to re-examine current contingency plans which may not be adequate for dealing with bird flu.

Some banks in Europe have already been working plans to deal with a possible avian flu pandemic.

HSBC has estimated that a widespread bird flu pandemic could affect up to 50% of its global staff. The bank has been preparing for staff that have to care for family members to work from home using video link and teleconference facilities and is also planning for office cleaning once an hour in an effort to limit infection.

HSBC's 50% figure is higher than official forecasts, including estimates from the World Health Organisation (WHO) which is expected to advise companies to plan for 25% absence.