The changes would extend the minimum period Hongkongers must stay in Taiwan to become eligible to apply for permanent residency, from one year to at least four years.

The council is considering amending the “Regulations Governing Permits for Hong Kong and Macau Residents Entering the Taiwan Area and Setting Up Residence or Registered Permanent Residence in the Republic of China”, a government official said on Sunday, speaking on condition of anonymity.

The official said that national security agencies are concerned that China might try to infiltrate Taiwan through Hong Kong.

According to the proposed amendment, Hongkongers born in Hong Kong and with no relatives in mainland China would need to stay in Taiwan for four years before they can apply for permanent residency.

Mainland Chinese with permanent residency in Hong Kong would need to stay for at least six years before they can apply, similar to Chinese spouses of Taiwanese.

Current regulations stipulate that Hong Kong and Macau residents who have lineal relatives or a spouse with a household registration in Taiwan, have received “overseas compatriot education” or contributed to overseas community affairs before the UK or Portugal ended their governance of the territories, invested more than NT$6 million (US$195,185) in Taiwan, or have passed review by a central competent authority can apply for permanent residency after staying in Taiwan “for a period of time.”

The official said the term “for a period of time” means they can apply for naturalization after staying in Taiwan for one year, which is a “quasi-national treatment,” as other foreign nationals must stay for five years before they can apply for naturalization.

Hong Kong residents who held a Taiwanese identity card before 1997 were considered Taiwanese citizens, so under the special circumstances, the government at the time granted Hongkongers “quasi-national treatment,” allowing them to be naturalized after staying in Taiwan for one year, the official said.