Last week, China sent several jets across the mid-line of the sensitive Taiwan Strait that the Taiwan military views as “harassment and threats” from Beijing.
Recent months have shown troubling signs of growing tensions between Taipei and Beijing which claims democratically-run Taiwan as its own territory, to be taken by force if needed.
Chinese aircraft crossed the mid-line to enter the island's air defense identification zone on Friday and Saturday, prompting Taiwan to scramble jets to intercept them, and President Tsai Ing-wen to call China a threat to the region.
In a statement, Taiwan's Defense Ministry said it had "clearly defined" procedures for the island's first response amid "high frequency of harassment and threats from the enemy's warships and aircraft this year".
It said Taiwan had the right to "self-defense and to counter-attack" and followed the guideline of "no escalation of conflict and no triggering incidents".
Taiwan would not provoke, but it was also "not afraid of the enemy", it added.
Taiwanese and Chinese combat aircraft normally observe the mid-line of the Taiwan Strait and do not cross it, although there is no official agreement between Taipei and Beijing on doing so, and the rule is observed unofficially.