All of Hong Kong's 28 retail banks, including digital lenders, will fully launch a new service called Money Safe on Wednesday.

According to the Hong Kong Monetary Authority (HKMA) and the Hong Kong Association of Banks (HKAB), Money Safe is an optional service that allows customers to lock up their bank account balances, with additional verification procedures required if users wish to withdraw or transfer their funds.

Authorities likened the service to "a safe within a bank account", saying it plays a key role in warding off fraud and scam activities.

Speaking at a press briefing, HKMA noted that over 3,200 customers have already been using the pilot service as of mid-December, locking in a total of HK$1.6 billion, or about half a million dollars on average per customer.

Arthur Yuen, HKMA's deputy chief executive, said while around three-quarters of these customers are people aged between 25 and 59 years old, he hopes users from other age groups will also sign up.

"We don't really set any targets, and we do think that Money Safe is good for everyone, so if we could be evenly spread out amongst different age groups that would be good," he said.

"But we also saw that elderly people tend to be easy prey for scammers, therefore, if it turns out that there are more people aged 60 and above using it, that would be good as well.”

Yuen added that for digital banks without physical branches, customers who've signed up for the scheme would have to head to their offices to undergo the extra verification process before "unlocking" their savings.

Separately, Alan Au, HKMA's executive director (banking conduct), said customers are free to cancel the service after confirming with bank staff.

"In some circumstances if the customer is not making an answer that seems to be normal, then bank staff can also offer to contact the family members of the customer or even contact the police," Au said.