President Lai Ching-te's government has clashed with the opposition parties that control parliament over how much to spend on improving Taiwan's defence capabilities.

China claims Taiwan is part of its territory and has threatened to use force to seize it.

Lai's government, which has been under intense US pressure to increase defence spending, wants to allocate up to NT$210 billion ($6.6 billion) over more than five years for Taiwan-made unmanned vehicles, including coastal surveillance, attack and surface drones.

The Kuomintang (KMT), Taiwan's main opposition party in favour of closer ties with China, has proposed NT$240 billion in spending over six years.

But the KMT wants to cap spending at NT$40 billion a year and include it in the annual budget.

Lawmakers voted Friday in favour of sending bills, including those proposed by the government and the KMT, to committees for review.

Lai has warned the KMT's proposal to include drone spending in the annual budget would reduce funds available for "other important public expenditures such as education and social welfare".

It would also make it difficult "to respond promptly to our military building needs", Lai said Wednesday.

But KMT lawmaker Jonathan Lin defended the proposal on Tuesday, saying the development of national defence was "a long-term undertaking" and special budgets should not be used "as a way to bypass oversight".

The United States' top envoy to Taipei insisted on Thursday that drones were a "game-changing opportunity" for Taiwan to boost its security and bolster regional peace.

"Nothing will deter conflict more effectively than turning Taiwan into a hornet's nest of air, surface, and subsurface drones," American Institute in Taiwan director Raymond Greene said, adding that it would require "deliberate investment".

In May, the KMT and the Taiwan People's Party passed a $25 billion special defence budget, slashing by a third the amount sought by Lai's Democratic Progressive Party.

The opposition stripped out around $15 billion that the government had wanted to use for domestic drone procurement and other efforts to boost defences.

Taiwan is a relatively new player in the increasingly competitive drone industry.

The island aims to have a monthly production capacity of 100,000 drones by 2030, compared with its previous target of 15,000 by 2028.