The club's letter, dated April 22 and signed by its president Keith Richburg, said it was concerned about recent discussions surrounding the possible introduction of a fake news law, which it said had been publicly supported by Tang as well as Chief Executive Carrie Lam.
The FCC said the matter is of serious concern to journalists, and it needed clarification on a statement Tang made at the Legislative Council on April 16.
It quoted him as saying, "For those endangering Hong Kong's security using fake news, we will launch an investigation right away, and when there is evidence, we will pursue a prosecution."
Tang was asked how he defines "fake news", given there is no fake news law in Hong Kong. The club also wanted to know what form of reporting would constitute fake news, and on what legal basis can it be investigated and prosecuted.
The FCC also asked, "How is your pledge to investigate 'fake news' compatible with previous promises by the government to protect press freedom in the city?"
The club elaborated on its concerns about the term "fake news", saying it is vague and subjective, and has been used by public figures to attack unfavourable coverage even when it is factually correct. It added that fake news legislation has been used in numerous countries to suppress press freedom and freedom of speech.
The letter ended with the reiteration of a long-standing invitation to the Hong Kong police to speak at the club, and for members to discuss their concerns with the force in person.
A small number of "unusual infections" have been identified in patients at the Royal Aberdeen Children's Hospital.