By Michael Bristow
BBC News, Beijing
China has warned that Taiwan President Chen Shui-bian's government will pay a "dear price" if he continues moves towards independence for the island.
UN membership is debated regularly in Taiwan
Jiang Enzhu, a parliament spokesman, said Beijing would "repulse" any pro-independence activities.
In a few weeks, Taiwan is due to hold a referendum on whether to apply to join the UN under the name Taiwan.
China considers Taiwan as part of its territory but the island has functioned independently for nearly 60 years.
Mr Jiang made the tough comments on Taiwan at a press conference outlining details for China's forthcoming legislative session.
"The attempts by the Chen Shui-bian authorities to push for a referendum on joining the UN under the name Taiwan is a... move towards 'de jure' independence for Taiwan," he said.
"If the Chen Shui-bian authorities should stubbornly continue down the path, they will surely pay a dear price."
He added that the referendum was tantamount to a referendum on Taiwanese independence.
Mr Jiang said China would pursue peaceful reunification between the two, but warned that there were other options available.
"We are fully prepared to repulse any adventurous activities aimed at Taiwan independence, and prevent anyone from separating Taiwan from China," he said.
China has previously threatened to attack the island - formally, and confusingly, known as the Republic of China - if it declares independence.
Taiwan has been self-governing since 1949, when the two sides split following a civil war in China.
But most countries officially recognise China's territorial claims over the island.
As well as holding a referendum later this month, Taiwan will also hold a presidential election.
The current president, independence-leaning Chen Shui-bian, will step down after eight years in office.