China has included the death penalty in its judicial guidelines for punishing "unwavering" advocates of an independent Taiwan.
The guidelines come into effect on Friday.
In a statement, Beijing makes it clear that the death penalty can be applicable to "leaders" of independence movements that "cause particularly serious harm to the state and the people", reports the regime-controlled news agency New China (Xinhua).
Other leading independence supporters may risk imprisonment from ten years to life.
According to the news agency, it concerns "separatists" and individuals who incite "activities that split the state". The statement is also directed at those who attempt to "change Taiwan's legal status as part of China".
Taiwan hits back, saying that China "has no legal jurisdiction whatsoever over Taiwan" and that the rules "have no binding effect on our people".
Taiwanese authorities believe that China's actions "will only provoke confrontation between the peoples on both sides of the Taiwan Strait", according to a statement.
China views self-governing Taiwan as part of its territory and has said it will take over the island eventually, by force if necessary.
In May, China held a military exercise near Taiwan – three days after Taiwan's elected president Lai Ching-Te was sworn in. China has branded him a "dangerous separatist" and "troublemaker".
