A businesswoman deposited the equivalent of almost US$2 million at a branch of China's largest bank but only US$20 remained after most of it was transferred without her authorisation, state media reported.

Wang Li was one of several victims of a scam, involving millions of dollars, at a branch of the state-owned Industrial and Commercial Bank of China (ICBC) in Shijiazhuang, highlighting increasingly sophisticated financial crime.

A branch executive persuaded her to put 10.8 million yuan ($1.7 million) in a one-year deposit programme offering interest rates more than three times the norm, China News Service reported.

But when she checked her account earlier this month it held only 124 yuan, the report on Tuesday stated.

She had never used the online banking security device she was given when she opened the account, it added -- but was later told that 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.

Dozens of other depositors at the branch made similar complaints, with the sums of cash involved amounting to "tens of millions of yuan", China News Service said.

It was not clear whether ICBC would compensate customers who have fallen victim to the scam.

ICBC official Sun Shifeng denied the branch had lured depositors with illegally high interest rates, adding it had reported the incidents to police, 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 rather than the culprit.

He was convicted of fraud in 2007, fined 100,000 yuan and sentenced to four years in prison, only to finally be cleared on appeal by a higher court late last year, the Changjiang Times reported in January.