China will hold those who support "Taiwan independence" criminally liable for life, it said on Friday.
It provoked anger and ridicule from the democratic island at a time of heightened tension across the sensitive Taiwan Strait.
For the first time, China was spelling out the punishment that awaits people deemed to back independence for Taiwan, top officials of the self-ruled island among them, as tension rises over what China regards as a province of its own.
China has not ruled out using force to bring Taiwan under its control, despite the island's claim that it is an independent country that will defend its freedom and democracy.
The Taiwan Affairs Office named Taiwan Premier Su Tseng-chang, Parliament Speaker You Si-Kun and Foreign Minister Joseph Wu as being "stubbornly pro-Taiwan independence", as it made public for the first time that it had drawn up a list of those falling into the category.
China will enforce punishment for those on the list by not letting them enter the mainland and its Special Administrative Regions of Hong Kong and Macau, spokeswoman Zhu Fenglian said in a statement on Friday.
She added that such blacklisted individuals will not be allowed to cooperate with entities or people from the mainland, nor will their companies, or entities that fund them, be allowed to profit from the mainland.
Taiwan's Mainland Affairs Council admonished China, saying Taiwan was a democratic society with the rule of law and not ruled by Beijing.
"We do not accept intimidation and threats from an autocratic and authoritarian region," the council said, adding that it would take the "necessary countermeasures to safeguard the safety and well-being of the people".
Zhu said the message China wanted to send to supporters of Taiwan independence was: "Those who forget their ancestors, betray the motherland and split the country, will never end up well and will be spurned by the people and judged by history."
In a Twitter post on Saturday, Taiwan's foreign minister, Joseph Wu, wrote, "I've received countless notes of congratulations after being blacklisted and sanctioned, for life, by the #CCP," referring to the Chinese Communist Party.
"Many are jealous for not being recognized; some ask where they can apply for it. To deserve the rare honour, I'll keep fighting for #Taiwan's freedom and democracy."
China believes Taiwan President Tsai Ing-wen is a separatist bent on declaring formal independence. She says Taiwan is already an independent country called the Republic of China, its formal name.