The government has refused to explain the decision despite calls from the public and rights groups, and criticism from foreign governments including Britain and the United States.
Hong Kong: Hong Kong's powerful bar association, a group of the city's top lawyers, has upped pressure on the government to explain the blacklisting of a British journalist in what was widely seen as an unprecedented attack on press freedom.
Victor Mallet, a senior journalist with the Financial Times, was refused a work visa extension and then barred from entering the city as a tourist after he chaired a talk by an independence activist at the city's press club.
The effective blacklisting of Mallet comes as concern grows that Hong Kong's cherished freedoms are disappearing as Beijing tightens its grip on the semi-autonomous city.
In a statement late Thursday the bar association said the rights enshrined in Hong Kong's mini-constitution, including freedom of expression, should be respected "whether one agrees with the information or ideas or not".
"The HKBA considers that the public, both domestically and internationally, is justifiably concerned whether the decisions (over Mallet's visa and entry to Hong Kong) constitute undue interferences with the right to freedom of expression," it added.
It urged the government to explain the decisions "so that the public can see if good reasons exist for them".
A report from the US-China Economic and Security Review Commission this week said there had been a "steady erosion" of Hong Kong's autonomy under President Xi Jinping and cited Mallet's visa denial as an example of challenges to freedom of speech.
"Beijing's encroachment on Hong Kong's political system, rule of law and freedom of expression is moving the territory closer to becoming more like any other Chinese city," the report said.
USCC, a congressional body that monitors national security and trade issues between the US and China, also called on the US Department of Commerce to publish assessments of the safety of exporting sensitive technology to Hong Kong.