Police are investigating the disappearance of tens of millions of yuan deposited in branches of the Industrial and Commercial Bank of China in Shijiazhuang, capital of north China's Hebei Province.
The scandal came to light after a customer, Yu Bing found that the 3 million yuan (U.S.$483,300) he had deposited had disappeared, China News Service reported.
Yu had heard that ICBC was offering an interest rate of 8 percent with a one-year maturity, the report said.
In April last year, he opened an online account with the bank but 12 months later found that only dozens of yuan remained. When the bank checked its records it found that the money had been transferred three days after he made the deposit, the report said.
Dozens of other depositors made similar complaints, with the sums involved amounting to "tens of millions of yuan," the report said.
Wang Li, a businesswoman, deposited the equivalent of almost U.S.$2 million, but only U.S.$20 remained after most of it was transferred without her authorisation.
A branch executive had persuaded her to put 10.8 million yuan in a one-year deposit program offering interest rates more than three times the norm, the report said.
She had never used the online banking security device she was given when she opened the account, according to AFP, but was later told the device had a different serial number to the one she had signed for, implying that the genuine one may have been used to access her funds.
Other depositors' USB keys were also found to be fake.
ICBC official Sun Shifeng denied that the bank lured depositors with illegally high interest rates, adding that it had reported the incidents to the police, according to the China News Service report. Sun said bank employees had been questioned, but he didn't give any details, the report said.
Banking scams are rife in China, sometimes involving bank employees, and ordinary savers are often the ones robbed.
Zhang Jing sued the Agricultural Bank of China in the southwestern city of Chongqing after an employee transferred more than 1.2 million yuan out of his and his wife's accounts, but during the proceedings he was arrested.
He was convicted of fraud in 2007, fined 100,000 yuan and sentenced to four years in prison. He was cleared last year.
