Taipei, Taiwan - Taiwanese President Lai Ching-te said Wednesday his government will propose $40 billion in additional military spending over eight years as tensions with China continue to rise.

Taiwan has ramped up defense spending in the past decade as Chinese military pressure intensified, but US President Donald Trump's administration has pushed the island to do more to protect itself.

Lai said the military aimed to have a "high level" of joint combat readiness against China by 2027 – which US officials have previously cited as a possible timeline for a Chinese attack on the island.

"The ultimate goal is to establish defense capabilities that can permanently safeguard democratic Taiwan," Lai said at a news conference, after announcing the $40 billion spending plan in a Washington Post opinion piece.

China claims the island is part of its territory and has threatened to use force to annex it. Beijing's foreign ministry warned Wednesday that Taiwan's "attempts to resist unification and seek independence through military means will never succeed".

Lai's announcement came as Tokyo and Beijing were locked in a weeks-long diplomatic spat that followed remarks by Japanese Prime Minister Sanae Takaichi suggesting Japan could intervene militarily in any attack on Taiwan.

Raymond Greene, the top US envoy as director of the American Institute in Taiwan, said he "welcomes" the government's spending plan and urged the island's rival political parties to "find common ground" on boosting its defenses.

Lai said the extra spending would go towards new arms purchases from the US and enhancing Taiwan's ability to wage asymmetrical warfare, as well as a so-called "T-Dome" air defense system.

He insisted the purchases are not tied to Taiwan's ongoing tariff negotiations with the Trump administration, insisting the main goal was to "demonstrate Taiwan's determination to defend" itself.

"We aim to bolster deterrence by inserting greater costs and uncertainties into Beijing's decision-making on the use of force," Lai said in the Washington Post.

His comments also follow US approval this month for $330 million-worth of parts and components.

Lai's government may struggle to get the proposed spending approved by parliament, where the main opposition Kuomintang (KMT) party, which advocates closer ties with China, controls the purse strings with the help of the Taiwan People's Party.

KMT chairperson Cheng Li-wun has previously opposed Lai's defense spending plans and on Wednesday warned he was "playing with fire" and risked turning the Taiwan Strait into a "powder keg".

KMT lawmaker Ma Wen-chun said bolstering national defense was "not about shouting slogans or simply buying more weapons."

Recruiting and retaining more troops was a "far more urgent and important issue" for the military, Ma said.

"In the future we may face a situation where there are no personnel left to operate these weapons."