One of them was asked to pay HK$300,000, the city's biggest pro-establishment party said.

This came as Edward Leung Hei, a Legislative Council member for the Democratic Alliance for the Betterment and Progress of Hong Kong, invited three victims of credit card fraud, who were required by banks to pay for the unauthorized transactions, to share their experience yesterday.

A woman, Cheung, had three credit cards and Hong Kong identity card stolen last year, and fraudsters used her cards to pay for HK$300,000 in purchases. HSBC asked her to pay the bill, citing her "serious negligence."

Cheung said: "The pickpocket did not steal my wallet, but just my ID card and three credit cards, one with Standard Chartered, two with HSBC, in my wallet. So I did not realize my credit cards were stolen until I received an SMS message from HSBC informing me that I'd spent HK$300,000 with my credit card to buy a watch."

She froze her cards within 10 minutes after receiving the message and reported to the police.

Two months later, StanChart had waived the spending carried out by the fraudsters, but HSBC insisted on her paying for the HK$300,000.

Having battled with HSBC for seven months, she still cannot get it waive the bill, and Cheung said this has taken a mentally toll on her.

"The only thing I regret is having HSBC credit cards," Cheung said.

"I used to spend only by hundreds or thousands of dollars, and this transaction is clearly a radical departure from my spending pattern, but the bank did not take any verification measures such as sending me a one-time pin. They would rather shift the responsibility to clients than admit their security system is imperfect."

Another holder, Lee, also had three of his credit cards, and the fraudsters used all his credit allowance to run up spending of more than HK$700,000.

"Two of the banks have waived the fraudulent transactions after I proved I did not authorize them, but HSBC insisted on me paying for my 'serious negligence,'" Lee said, adding he is still responsible for the loss even after the suspects were caught.

"Card-issuing banks reserve the ultimate power to define 'serious negligence,' and that is why our victims still need to pay for their loss," Leung said.

"Authorities should proactively reach out to banks and clearly define 'serious negligence' so they can better inform people to avoid falling into the trap."

Leung said banks should not just profit from clients' data but should utilize it to better protect their funds.

"Banks should consider requiring verification codes for those transactions that are inconsistent with card holders' consuming patterns," he said.

A HSBC spokesman said: "We understand the concerns of affected clients and have been following up with them and related institutions.

"We also frequently remind the public to take good care of their credit cards and keep their personal data, such as one-time pins, in confidence."

Last year saw a 45.1 percent increase in credit card fraud cases compared to 2021, logging 77 cases a day on average.