Hundreds of customers descended on branches of Hong Kong-based Bank of East Asia on Wednesday to demand their deposits back after the bank was hit by doubts about its stability.

In one of the first bank runs in Asia since the current international financial crisis began, customers lined up outside BEA offices across the territory.

The mid-sized lender insisted that "malicious" rumours spread by cellphone text messages in recent days have no basis in fact.

"The Bank of East Asia is not suffering from financial difficulties. We have enough cash to handle the needs of depositors," deputy chief executive Joseph Pang told reporters.

He declined to specify how much money customers have withdrawn, but said it was not a large amount and no major clients had pulled their money.

The bank offered assurances that its capital ratio was well above international standards. Seeking to calm investors, it also disclosed that its exposure to failed U.S. financial companies Lehman Brothers Holdings and American International Group was about $61 million.

The company's stock tumbled almost seven per cent.

With debt and credit problems roiling the world's financial institutions, many of the bank's depositors were less than assured.

"I'm very afraid. I'm very worried," said Cindy Li, a 48-year-old waitress who showed up at the bank's headquarters to withdraw her entire savings of more than $26,000.

"I don't know what the world has come to. It's better if I keep my money on hand."

The rumours apparently emerged after Moody's Investors Service changed its outlook on BEA's credit rating from stable to negative on Friday, citing a recent insider trading case that exposed "lacklustre internal controls."

Last week, the bank revealed a trading loss of $12 million blamed on a rogue equity derivatives trader who manipulated valuations to hide losses. The discovery forced the bank to revise down its earnings for the first half of the year.

The Hong Kong Monetary Authority said the banking system as a whole is "safe and sound."

"I can confirm, categorically, that these rumours are unfounded," said Joseph Yam, the authority's chief executive. "It is a very sound bank."