Two suspects allegedly set up 10 shell companies and opened 13 corporate accounts to handle HK$5.5 billion in criminal proceeds.
According to Australian police, Sydney-based syndicate acted as unregulated multinational bank.
Hong Kong police have arrested 633 people accused of handling HK$7.8 billion (US$994 million) in suspected criminal proceeds, including two men who helped process HK$5.5 billion in connection to a major bust led by the Australian force.
The two suspects, 29 and 38, were arrested on February 2 as part of an international operation led by the Australian Federal Police. Officers were still searching for two other men, Hong Kong police on Friday said.