Chen Shui-bian, the Taiwanese president, "is determined to push 'Taiwan independence' to create antagonism and conflict within Taiwan and across the strait," the Communist Party and the government said on Tuesday in a joint statement carried by the official Xinhua News Agency.
"It will only bring disaster to Taiwan society," the statement said.
Chen announced on Monday that he was terminating the National Unification Council and doing away with its guidelines, which commit Taiwan to eventual unification with the mainland. He also said that it did not mean the self-ruled island would push for formal independence.
Taiwan and China split amid civil war in 1949, but Beijing considers the island 160km across the Taiwan Strait to be Chinese territory. It has repeatedly threatened to attack if Taiwan tries to make its de facto independence official.
A Chinese newspaper called Taiwan president's scrapping of a body on reunification "provocative" and said the move marked a step towards independence that could endanger peace in the region.
The state-run China Daily wrote in an editorial: "His further escalation of secessionist activities will no doubt stoke tensions and trigger a serious crisis in the Straits."
The paper added: "Chen's risky and provocative actions also threaten to destroy peace and stability in the Asia-Pacific region."
It accused Chen, whose pro-independence Democratic Progressive Party took power in 2000 and narrowly won re-election in 2004, of pushing independence as a means of deflecting criticism over what it said were his political and economic failings.