Police are urging users of the popular online trading platform Carousell to be vigilant against bogus payment links aimed at hacking into their bank accounts, with 644 cases recorded in the first 10 months of the year, incurring losses of HK$36 million.

The new tactic emerged as the force noted a 23.7 percent year-on-year rise in the overall number of online shopping scams during the same period, and the amount involved more than doubled to HK$332 million.

To make transactions safer, Carousell introduced a Buyer Protection service in August, through which the seller only receives payment after the buyer confirms receipt of the goods.

But senior inspector Victoria Ng of the Cyber Security and Technology Crime Bureau said the number of scams surged after the service was rolled out, with 330 cases recorded alone between August and October, involving HK$25 million.

She explained scammers would pose as buyers and offer to pay for the item through the new payment system.

The sellers, after providing an e-mail address, would then receive a phishing link, which directs them to a website asking for details of their online banking account.

The sellers could then withdraw all the money from the victims’ accounts.

Carousell chief of staff Tan Su-lin clarified users never have to surrender their e-mail address when using the payment system, let alone click on links.

“In today's day and age, it's really a very risky behaviour to click on any links that you receive, whether it's via e-mail, or through your WhatsApp,” she said.

But not just sellers are being scammed - chief inspector Felton Leung noted buyers seeking sought-after items, such as concert tickets, can also fall prey to deception.

“The scammers … play mind games with the victims. They knew that the victims want [the product] so much and it's so hard to get in any other places, so they will put on some time frame or time constraint on the victims. If they don't settle the deal as soon as possible, they will not get the tickets.' he explained.

Police advised buyers to stick to official or reputable sellers, and ask to trade in person whenever possible.