According to the current rules from Hong Kong's banking association, banks are instructed to disclose linked property of clients found in violation of the city's national security law.

The guidance was first published on the Hong Kong Monetary Authority's website on Oct. 22 in an update of the Hong Kong Association of Banks' (HKAB) frequently asked questions concerning anti-money laundering and counter financing terrorism (HKMA).

The following information from law enforcement agencies: Banks should reveal property held by any client arrested or charged for an offense damaging national security or when they know or suspect that a property is "offence related property."

The HKMA or the HKAB did not immediately return a Reuters request for comment.

On June 30 of last year, China enacted national security legislation in Hong Kong, making anything Beijing considers subversion, secession, terrorism, or cooperating with foreign forces criminal by up to life in jail.

Three months later, the banking association added five paragraphs to the anti-money laundering and counter-financing terrorist FAQs, informing banks of their legal reporting obligations, how to handle law enforcement inquiries, and group-wide information sharing rules.

According to the clauses in place, transactions suspected of being related to the law should be treated the same as transactions suspected of money laundering or financing terrorism.

The following questions and answers are not official guidelines, but they apply to Hong Kong and overseas banks.