At a briefing on Wednesday, police said 956 cases of phone scamming involving around HK$470 million were reported from January to July this year, a 60 percent increase year on year.

There was an 87 percent rise in the number of ruses involving people impersonating officials, which accounted for around 60 percent of all the scams.

Health authorities received numerous reports that fraudsters will use recording messages or lure people to join WhatsApp groups by claiming to be health officials.

"Authorities will not ask any person to provide personal information like bank accounts or credit card numbers," said Albert Au Ka-wing, Principal Medical and Health Officer of the Communicable Disease Branch of the Centre, "let alone calling people with recording or voice messages."

In a video played by police, an anonymous female victim described how she received a call from someone claiming to be an official who accused her of violating coronavirus restrictions.

"The caller could tell me all my personal information so I wasn't sceptical," she recalled.

She said she then had a video call with a uniformed man who claimed to be a security official in Guangdong -- a Chinese province neighbouring Hong Kong -- who demanded her bank log-in details.

The largest scam so far this year involved HK$65 million and was carried out by people claiming to be officials from Beijing's Liaison Office in Hong Kong and China's top prosecuting body.

The force arrested 173 people engaged in 386 phone scam cases during operations across the city from August 21 to September 18.

Among the 127 male and 46 female arrestees aged 13 to 72, most impersonated government officials to lure citizens into transferring money to their accounts. Ninety-one cases were reported to be "Guess who I am" telephone fraud.

A 13-year-old schoolboy was arrested for asking for bail from an elder claiming his son was in custody. Police also found him engaged in multiple fraud cases involving money from HK$1,500 to 3,000.