China, which views democratically governed Taiwan as its own territory, has a strong dislike of Lai, believing him to be a dangerous separatist, whose repeated offers of talks it has rejected, including one this month.

Lai, like current President Tsai Ing-wen, rejects Beijing's sovereignty claims; both say only the island's people can decide their future. Lai, now vice president, will be inaugurated on May 20.

"Before and after May 20, our nation's military will uphold all combat readiness requirements and pay close attention to the damaging of regional peace and stability by the other side," Deputy Defence Minister Po Horng-huei told reporters.

Chinese military activities in and around the Taiwan Strait are destabilising for the whole Indo-Pacific region, Po added in the comments made to reporters at parliament.

China's defence ministry did not immediately respond to a request for comment.

During the past four years, China's military has massively increased its activities around Taiwan, such as by regularly flying warplanes over the median line of the Taiwan Strait, which previously served as an unofficial buffer zone.

In Wednesday's daily report of Chinese military activities in the previous 24 hours, Taiwan's defence ministry said six Chinese aircraft had crossed the median line, flying in an area to the west of Taiwan's Penghu islands, home to a major air force base.

China, which has also staged at least two "joint combat readiness patrols" near the island in the past month, according to Taiwan's defence ministry, says it does not recognise the existence of the median line.

Taiwan-based security sources have repeatedly warned that China could show its displeasure with Lai using the military.

In 2022, China held major war games near Taiwan after a visit to Taipei by then-U.S. House Speaker Nancy Pelosi, and again last year after President Tsai met her successor, Kevin McCarthy, on a stopover in California.