Police have urged the public to beware of mainland stock investment scams in wake of a surge to 79 cases in the first quarter from one a year ago.

The cases, involving mostly local victims aged 17 to 86, were reported to have accumulated a loss of HK$487 million in total and accounted for 43 percent of the total losses from scams.

Commercial crime bureau chief inspector Or Wing-yan said the number of investment scam cases surged 4.5 folds to 2,850 cases in 2022 from 510 in 2020 with the number "continuing to rise this year."

"Normally, it would take six months to a year for investment scam victims to realize they had been cheated," Or said.

"But we are seeing a trend that the period shortens to three months for these mainland stock investment scams."

She said the criminals usually approached victims on social media, claiming they could buy mainland stocks not available on the Shanghai-Hong Kong Stock Connect and Shenzhen-Hong Kong Stock Connect with the promise of higher returns.

Hong Kong Securities and Futures Professionals Association chairman Mofiz Chan reminded investors the two official trading connects are the only legal ways for Hongkongers to buy mainland stocks.

Police said scammers then added the victims to group chats on instant messaging apps like WhatsApp to share so-called "insider tips" as well as sending them a hyperlink to ask them to create an account om a fake investment platform.

Victims were then asked to top their accounts with funds by transferring money to designated bank accounts that were mostly local personal accounts.

In one case, a 66-year-old retired male nurse lost HK$4.51 million.

In another case, a 50-year-old jobless man claiming to have over 10 years of investment experience lost HK$1.22 million. The jobless, Lee, was approached on the social media in January by scammers pretending to be mainland stock experts.

"I was suspicious of the bank accounts, but lowered my guard after seeing my account topping up after the transaction," Lee said.

After earning more than 10 percent, he attempted to withdraw the money but was denied. Lee was requested to pay HK$100,000 to "unlock" his account. The bogus expert also became unreachable.

Lee found he was not alone as other victims were also unable to access their "investment accounts".

Senior police inspector Ng Chun-yiu said suspicious hyperlinks and personal bank accounts could be the signs of potential scams and the police has an online scam-checker called "Scameter".

Ng said insider dealing is illegal and punishable by up to 10 years in jail and HK$10 million in fine.

Warning on mainland stock scams as cases rise