Police say Hong Kong's overall crime rate jumped 8.7 percent last year compared to 2021, driven by a surge in fraud cases.

There were slightly more than 70,000 cases of all types, with 40 percent of them related to scams.

The 28,000 or so scam reports received was a 45 percent rise on the number in 2021.

At a special Legco security panel meeting, police chief Raymond Siu said other serious crimes, such as burglary, wounding and arson, dropped to their lowest levels in decades.

But fraud victims lost some HK$4.8 billion between them, with most of the offences linked to the internet in one way or another.

Job scams jumped more than four-fold last year, with victims losing around HK$480 million in total. Investment scams netted fraudsters around HK$1.8 billion, and they raked in about HK$1 billion through phone scams.

Siu said the force increased its efforts to warn people about how scammers operate, but victims often tell officers they hadn't paid much attention to the publicity campaigns.

"Many of the victims, when we talk to them, they know that we have anti-deception publicity. But when asked whether they have looked into the content, they say, no," the police commissioner said at a press conference.

He said his officers have been "force-feeding" the public warnings about scams even if they're not interested, by placing adverts before movie screenings and public announcements aimed at motorists as they drive through tunnels.

Siu said police are in talks with telecommunication firms about whether a verification system can be set up for text messages so people can have faith that the sender is trustworthy, and discussions are also taking place on whether the companies can intercept scam-related hyperlinks in messages.

Meanwhile, Siu said a total of 236 people have now been arrested on suspicion of violating the national security law, with 140 of them charged.

The National Security Department Reporting Hotline has received more than 400,000 messages since its launch in November 2020, while more than 13,000 reports have been made to a counter-terrorism hotline since last June, police said.