China has been incensed by recent moves by US President Donald Trump's administration to increase support for self-ruled and democratic Taiwan, including US Navy sailings through the Taiwan Strait.

Speaking at the Shangri-La Dialogue in Singapore, Asia's premier defence summit, Wei said China would "fight to the end" if anyone tried to interfere in its relationship with Taiwan, which Beijing considers a sacred territory to be taken by force if necessary.

Wei, the first Chinese defence minister to speak at the Shangri-La Dialogue since 2011, said Beijing's military operations in Asia were purely aimed at self-defence, but it would not hesitate to counter an attack on its interests.

"China will not attack unless we are attacked," Wei said, cautioning that there would be dire consequences to any clash between China and the United States.

"The two sides realise that conflict, or a war between them, would bring disaster to both countries and the world."

The United States, like most countries, has no formal ties with Taiwan, but is its strongest backer and main source of weapons.

On Saturday, acting US Defence Secretary Patrick Shanahan told the Shangri-La meeting that the US would no longer "tiptoe" around Chinese behaviour in Asia.

While Shanahan's speech was critical of China, his tone was often conciliatory. Wei took a more combative approach.

"No attempts to split China will succeed. Any interference in the Taiwan question is doomed to failure," said Wei, dressed in his uniform of a general in the People's Liberation Army.

"If anyone dares to split Taiwan from China, the Chinese military has no choice but to fight at all costs ... The US is indivisible, and so is China. China must be, and will be, reunified."

China-US ties have become increasingly strained due to a bitter trade war, US support for Taiwan and China's muscular military posture in the South China Sea, where the United States also conducts freedom-of-navigation patrols.

In May, Taiwan's national security chief David Lee met White House national security adviser John Bolton, marking the first meeting in more than four decades between senior US and Taiwanese security officials.

This week will mark 30 years since a bloody Chinese military crackdown on protesters around Beijing's Tiananmen Square, refocusing scrutiny on China's approach to security threats.

Wei defended the government's handling of the Tiananmen "incident", a rare official acknowledgement of the events of June 4, 1989; references to it are heavily censored in China.

"The government was decisive in stopping the turbulence," Wei said of the Tiananmen Square crackdown.

"Due to this, China has enjoyed stability, and if you visit China you can understand that part of history."

On the ongoing trade war Wei said China would "fight to the end" if the United States wanted a fight. But if Washington wanted to talk, "we will keep the door open".

Australian Associated Press