Taiwan's President Chen Shui-bian has signed a controversial law which allows the island to hold referendums.
Mr Chen wants a referendum to coincide with next year's elections
The law's passage has infuriated China, which fears it could be used to move Taiwan towards formal independence.
President Chen has pledged to use one clause of the bill to allow him to hold a poll on whether China should remove hundreds of missiles pointed at Taiwan.
Critics say he is using the issue to help his chances of re-election in presidential polls set for 20 March.
On Wednesday, a Chinese official said Mr Chen had "fanned anti-mainland sentiment for his own selfish interest and for the elections".
Zhang Mingqing, spokesman for China's policy-making Taiwan
Affairs Office, told a news conference that Mr Chen was "immoral".
China views Taiwan as part of its territory, and has threatened to use force if the island declared independence.
But Mr Chen brushed off the latest criticism, calling the law's passage "truly a historical moment".
The new law, which was considerably watered down by the opposition Kuomintang (KMT), takes effect on Friday.
Under its provisions, the president can only initiate a referendum if the island is deemed to be under imminent attack.
Mr Chen has said the precondition has already been met because China has deployed several hundred missiles across the Taiwan strait.
Mr Chen's plan to hold a poll to coincide with the presidential poll has alarmed some of his allies, including the United States.
US President George W Bush issued a measured warning to Mr Chen earlier this month when he said: "The comments and actions made by the leader of Taiwan indicate that he may be willing to make decisions unilaterally, to change the status quo, which we oppose".