Act Governing Relations with Hong Kong and Macau Article 33

Relevant rules of the Act for Foreign Exchange Control shall apply mutatis mutandis to the regulation in the Taiwan Area of currency and negotiable instruments issued in Hong Kong or Macau, as long as they are fully backed by reserves and freely convertible.In the event that the preceding conditions are not met, or if other major circumstances arise and are deemed harmful to the financial stability of the Taiwan Area, or as likely to seriously affect the financial policies of the Taiwan Area, then the inflow and outflow, exchange and other trading activities involving said currency and negotiable instruments in the Taiwan Area may be restricted or prohibited by the Central Bank of China in conjunction with the Ministry of Finance. However, said currency and negotiable instruments, if declared voluntarily to customs upon entry, may be taken out of the Taiwan Area.
中文原文 香港澳門關係條例第33條
香港或澳門發行幣券在臺灣地區之管理,得於其維持十足發行準備及自由兌換之條件下,準用管理外匯條例之有關規定。
香港或澳門幣券不符合前項條件,或有其他重大情事,足認對於臺灣地區之金融穩定或其他金融政策有重大影響之虞者,得由中央銀行會同財政部限制或禁止其進出臺灣地區及在臺灣地區買賣、兌換及其他交易行為。
但於進入臺灣地區時自動向海關申報者,准予攜出。

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