Regulations Governing the Management of Import/Export Clearance for Transportation means Article 54

The Customs may from time to time send its official to board any vessel within the waters 24 nautical miles from the coastline of the Republic of China and conduct inspection.
中文原文 運輸工具進出口通關管理辦法第54條
船舶在中華民國沿海二十四海里以內之水域時,海關得隨時派員登船檢查。

English translation for reference only; the Chinese text prevails. Not legal advice.