China's parliament passed today a contentious anti-secession bill that mandates the use of military force against Taiwan if the self-ruled island Beijing claims as its own formally declares statehood.

China hopes the law will deter Taiwan President Chen Shui-bian from pushing for the democratic island's independence during his second and last term that ends in 2008, analysts say.

The bill, which stipulates China would only resort to "non-peaceful" means against Taiwan as a last resort, could increase tension in one of the most dangerous regions in Asia.

Chen has denounced the bill as a threat to regional security and sought to rally Taiwan against it.

Despite the legislation, analysts say the People's Liberation Army has no immediate plans to attack Taiwan, over which Beijing has claimed sovereignty since Nationalist troops lost the Chinese civil war on the mainland and fled to the island in 1949.

The bill, which is expected to see unanimous support when parliament delegates vote this morning, is mainly designed as a warning to Taiwan independence backers. The final day of the annual parliament session opens at 0100 GMT (1200 AEDT).

"I don't think they will immediately attack after enacting this legislation. Nor do I think that they don't dare attack without this law," said Jin Zhong publisher of Hong Kong's Open weekly magazine.

"They're using legal means to increase threats against Taiwan ... No one will dare raise his hand and vote against it."

Parliament's legal committee had made some revisions and recommended the law be submitted to parliament for adoption, the official Xinhua news agency said today. The changes amounted to minor tweaks of the draft.

The bill stresses China could resort to "non-peaceful" means - not specifically war - leaving Beijing options like economic sanctions or blockades, language analysts said are designed to allay fears in Taiwan, Japan and the United States, which has sworn to defend the island.

The legislative sleight of hand doesn't appear to have worked however.

A White House spokesman has called the bill unhelpful and asked China to reconsider it, remarks Beijing later rejected as irresponsible. President Chen's Democratic Progressive Party plans a 500,000-strong protest march later this month.