The future of foreign judges, including three Australians, serving on Hong Kong's top court is in doubt due to concerns about the territory's national security laws which lawyers say have undermined the independence of the city's British-style legal system.

The Hong Kong government revealed on Friday that Australian judge James Spigelman had resigned from Hong Kong’s Court of Final Appeal two years before his term was due to expire. Chief executive Carrie Lam revoked his appointment as one of 14 non-permanent overseas judges on September 2.