WASHINGTON • Defence spending in Taiwan has not kept pace with the threat posed by China and should be increased, a senior US defence official said, amid a storm over US President-elect Donald Trump's questioning of American policy over the island.

Deputy Assistant Secretary of Defence Abraham Denmark said on Tuesday that the Obama administration's "one China" policy remains unchanged, but he could not predict Mr Trump's intentions when he takes office on Jan 20.

Mr Trump set off a diplomatic firestorm at the weekend when he questioned why the United States should be bound by the longstanding policy under which Washington recognises Beijing rather than Taiwan, which China considers a renegade province.

This followed an earlier Chinese protest over Mr Trump's telephone conversation with Taiwanese President Tsai Ing- wen on Dec 2, the first involving a US president-elect or president since 1979.

Some US analysts warn that Mr Trump could provoke a military confrontation if he presses the Taiwan issue too far.

Mr Denmark told the Project 2049 Forum in Washington that the main focus of China's military modernisation programme was to achieve reunification with Taiwan, by force if necessary.

"This makes it incumbent on Taiwan to prepare and invest in capabilities to deter aggression and mount an effective defence if deterrence fails," he said.

"Defence resourcing is critical. Taiwan's defence budget has not kept pace with the threat developments and should be increased."

The US is the main political ally and sole arms supplier to diplomatically isolated Taiwan, despite adhering to the "one China" policy.

In response to Mr Denmark's call, Taiwan's presidential office spokesman Alex Huang yesterday said Taiwan's military is formulating a new defence strategy to which the government plans to allocate more resources.

Meanwhile, Beijing has kept up its criticism of the recent moves by Mr Trump and Ms Tsai.

Mr An Fengshan, a spokesman for China's Taiwan Affairs Office, told a regular news conference yesterday that Beijing's stance of opposing and blocking "Taiwan independence splittism" is "firm and unmovable".

"We have unshakeable willpower, ample confidence and sufficient capability," he said.

"I think the facts tell these people that Taiwan independence is a dead end," he added.

REUTERS, AGENCE FRANCE-PRESSE