Although a standard patent application can be filed directly with Hong Kong and Macau IP directories, there are routes more convenient for obtaining patent protection in these two Chinese territories.

Extension of a patent application to Hong Kong

A standard patent can be obtained by extending a Chinese patent into Hong Kong. The extension procedure includes a two-stage recordation request, one occurs at the publication of the Chinese patent application and the other at the grant of the Chinese patent, each within 6 months from the publication or grant date. The Chinese patent/application has to be a patent type, instead of a utility model, and can be a national phase of a PCT application filed in any of the receiving offices.

The Hong Kong standard patent will have a patent term of 20 years starting from the application date of the Chinese patent and independent from the validity of the Chinese patent. That is to say, a Hong Kong standard patent can only be invalidated by filing a cancelation in Hong Kong separately, even if the corresponding Chinese patent is invalidated in Mainland China.

In addition to a Chinese patent, a European or United Kingdom patent can also serve as the parent patent for extending into Hong Kong, and follows the same procedure as stated above in reference to a Chinese patent.

Extension of a Chinese patent application to Macau

The extension procedure in Macau is similar to that of a Hong Kong standard patent originating from a Chinese patent, but a European or United Kingdom patent is not eligible for the extension.

However, Macau provides a more convenient route to extend a Chinese patent into Macau, i.e., extending a Chinese patent into Macau within 3 months from the grant date of the Chinese patent without the need of filing a first-stage extension request at the time of the publication of the Chinese application.

It should be note that, although Macau was a colony of the Portuguese empire, a Portugal or European patent is not eligible for patent extension into Macau, and the extension procedure applies to Chinese patent only.

Excerpt from:

Patents need to cover Hong Kong and Macau? Here's the procedure. - Lexology