Tensions have hit a new high between Taipei and Beijing, which claims the democratic island as its own territory, and Chinese military aircraft have repeatedly flown through Taiwan’s air defence identification zone.

Over a four day period beginning last Friday, Taiwan reported close to 150 Chinese air force aircraft entered its air defence zone, part of a pattern of what Taipei calls Beijing’s continued harassment of the island.

Asked by a lawmaker on the current military tensions with China at the parliament, defence minister Chiu Kuo-cheng said the situation was “the most serious” in more than 40 years since he joined the military, adding there was a risk of a “misfire” across the sensitive Taiwan Strait.

“For me as a military man, the urgency is right in front of me,” he told a parliamentary committee reviewing a special military spending of TW$240 billion (US$8.6 billion) for home-made weapons including missiles and warships.

China says Taiwan should be taken by force if necessary. Taiwan says it is an independent country and will defend its freedoms and democracy, blaming China for the tensions.

Chiu said China already has the ability to invade Taiwan and it will be capable of mounting a “full scale” invasion by 2025.

“By 2025, China will bring the cost and attrition to its lowest. It has the capacity now, but it will not start a war easily, having to take many other things into consideration.”

The US, Taiwan’s main military supplier, has confirmed its “rock-solid” commitment to Taiwan and also criticised China. Beijing blames Washington’s policies of supporting Taiwan with arms sales and sending warships through the Taiwan Strait for raising tensions.

Taiwan’s special military spending over the next five years will go mostly toward naval weapons including anti-ship weapons such as land-based missile systems.

Taiwan reported one Chinese air force aircraft entered its air defence zone on Tuesday.