The former Republican presidential candidate co-sponsored the bill with Sen. Tom Cotton R-Arizona, with the aim of demonstrating support for Hong Kong's autonomy as a Special Administrative Region (SAR) of China.
Rubio, who is co-chair of the Congressional-Executive Commission on China, said in a statement that the bill "would renew the United States' historical commitment to freedom and democracy in Hong Kong at a time when its autonomy is increasingly under assault."
The bill comes about after it emerged last year that five booksellers from the SAR
were either arrested in China or taken into the mainland by Chinese authorities. One bookseller was abducted in Thailand and another from the SAR itself.
One is a Swedish citizen, and another holds British passport.
Its legal independence was again rocked in recent weeks when the High Court chose to uphold a Beijing-issued ruling barring two elected lawmakers from taking office after they pointedly refused to swear an oath of allegiance to China. The two will appeal
Punitive measures proposed
The proposed legislation would allow the US to freeze assets and bar entry to people deemed responsible for "the surveillance, abduction, detention, or forced confessions of certain booksellers and journalists in Hong Kong, and other actions suppressing basic freedoms."
It would also ensure that those with criminal records resulting from pro-democracy activities, and would reinstate a requirement for an annual State Department report on the region.
Political analysts in Hong Kong welcomed the bill.
"At this stage we are not sure it will be passed but good sign that prominent members of congress are paying attention to freedom of expression" in Hong Kong, said Willy Lam, adjunct professor at the Centre for China Studies, Chinese University of Hong Kong.
"There are fears that after (President-elect Donald) Trump becomes President he might not be as concerned about China's human rights, as reports suggest that he wants to focus on the US," Lam told CNN.
"(Trump) has spoken out about China's (economic) behavior -- for example, currency manipulation -- but hasn't spoken out on China's human rights violations."
The same -- but different
Hong Kong's de facto constitution, the Basic Law, guarantees freedoms unknown in mainland China. It also prevents mainland officials from operating in the territory, which reverted from British rule to China in 1997. Under the Basic Law, Hong Kong's autonomy -- an arrangement known as "one country, two systems" -- is guaranteed for 50 years.
Hong Kong's legal separation from Beijing is a key factor for the city's economic well-being, with the rule of law which is enshrined in the document and its independent judiciary important considerations for the many multinational companies which operate out of Hong Kong.
"in recent years, Beijing has consistently undermined the 'one country, two systems' principle and infringed on the democratic freedoms the residents of Hong Kong are supposed to be guaranteed," Rubio's statement reads.
"This was on stark display over the last year with the abduction of the Hong Kong booksellers, the required loyalty oaths in the lead-up to the September LegCo elections, and last week with Beijing's unprecedented intervention in Hong Kong's legal system to block two democratically elected politicians from assuming office.
'Assault on democracy'
"China's assault on democratic institutions and human rights is of central importance to the people of Hong Kong and to its status as a free market, economic powerhouse and hub for international trade and investment."
His co-sponsor, Cotton, added that the bill would bring Hong Kong's political status was brought to the fore of the international community's attention.
"The United States must lead the world in ensuring that the Chinese government ceases any repressive acts in Hong Kong and abides by its three-decade-old international commitment to respect the autonomy of Hong Kong," he said.