Under the scheme, messages from major providers such as SmarTone, 3HK and 1010 will incorporate a hashtag as part of their sender IDs from December 28. The symbol is exclusive to registered parties.

Tsan said operators would have a four-month transition period to identify and fix any technical issues. Users could expect messages from providers that used or omitted the hashtag over the trial period, he added.

The watchdog had asked more than 100 service providers to join the scheme and was talking to banking industry leaders about joining the drive next month, he said.

“As the system is ready, we would like to kick-start its launch, and take it one step at a time to expand it to other industries,” Tsan said.

Earlier this year, the watchdog urged service providers to send out special voice or text messages alerting users to incoming overseas calls that carried Hong Kong’s “+852” dialling code.

Tsan said the most common phishing messages involved senders masquerading as telecoms operators or banks that slipped in hyperlinks to trick people into sharing their personal information.

He said he hoped the scheme could help to intercept messages typically sent en masse by scammers.

But the scheme had technical limitations, such as messages for data plans that required recipients to confirm their preferences, he said.

Tsan added that suspicious messages sent through WhatsApp and similar platforms would not be covered by the scheme as their operations were outside the authority’s control.

He also urged the public to check the list of registered operators on the authority’s website if they had any doubts.

Francis Fong Po-kiu, honorary president of the Hong Kong Information Technology Federation, said it made sense for service providers to join the scheme as they frequently sent messages.

“Adding a hashtag before the sender ID will hinder scammers sending mass messages to their targets,” he added.

Fong warned that the authority could not block all phishing attempts, but said the plan was still an “effective move” to intercept such messages.

He said he expected the verification measure would be the first step in raising public awareness about the need to verify suspicious messages.

IT-sector lawmaker Duncan Chiu said it was impossible to eradicate all scams as they evolved in parallel with technological advancement, but any moves put forward by the watchdog could be of help to stop one type of phishing at a time.

Chiu said the new drive could “test the water” for blocking mass text messages, but educating the public to stay alert to new scams was most crucial to tackle the problem.

“As long as there are people falling into the trap, scammers will take their chance,” he said.

He also urged the government to step up mass media promotions such as highlighting the latest scams on television every day.

While Tsan acknowledged WhatsApp and other texting tools were beyond the watchdog’s control, Chiu said the government should “add pressure” on the private communication platforms, instead of relying on their self-governance.

The Hong Kong Economic and Trade Office in Guangdong on Wednesday also reminded the public to remain vigilant against phone scams. It said fraudulent callers had recently started pretending to be from the office and the Shenzhen liaison unit.

The scammers typically asked recipients to disclose their personal information in a bid to verify their identities.

Police recorded a 52.1 per cent surge in all types of scams in the first 10 months of this year compared with the same period in 2022, rising from 19,444 cases to 29,650.

The amount of money lost to the scams was HK$4.99 billion (US$639 million) and represented a 47.6 per cent rise year on year.

According to official figures, 2,831 cases of phone deception were reported last year, a 148.3 per cent surge from 2021, with victims losing HK$1 billion.