Customs officers said on Saturday that they have arrested four people, aged between 32 and 54, on suspicion of laundering some HK$600 million.

The department accused the two men and two women, believed to be the core members of a money laundering syndicate, of using a number of bank accounts to handle suspicious funds between February 2020 and March this year.

Chan King-wai from the syndicate crimes investigation bureau said some of the money is believed to be related to a cryptocurrency trading platform.

"We believed the suspects aimed to utilise the high elusive nature of cryptocurrencies to help others handle money from unknown sources," Chan said.

He added that they might have handled funds through other bank accounts, including those of shell companies in Hong Kong.

Chan said some of the suspects claimed that their monthly income was around HK$20,000 to HK$30,000, and their companies did not have substantive business operations.

"Their bank accounts, however, have recorded transactions involving HK$600 million within 25 months, which were not commensurate with their reported financials, so we believed these four people were laundering black money," he said.

Customs officers said they are tracking down some of the suspicious funds, and more arrests could be made.