Robert French, a former Chief Justice of Australia's High Court, said he respected Hong Kong and the "integrity and independence" of the remaining foreign judges but that the "role of the non-permanent justices on the Court of Final Appeal has become increasingly anachronistic and arguably cosmetic".
The United Kingdom and China agreed to have non-permanent foreign judges on the court when the UK handed its former colony over to Chinese rule in 1997 under a "one country, two systems" formula.
Their presence was widely seen by lawyers, businesses and politicians as burnishing the city's rule-of-law credentials after it lost access to the UK's Privy Council for appeals.
Noting that the Hong Kong court was the only one in greater China to have foreign judges serving, French said there "may be a substantive role for international judges in Hong Kong in the future as part of an international commercial court".
The government confirmed the resignation in a statement, saying it was grateful to French for his valuable contributions and his "support for the rule of law in Hong Kong".
Last year, another non-permanent judge, the UK's Jonathan Sumption, quit the court shortly after a landmark verdict in which 14 prominent democratic activists were convicted for subversion, part of a national security crackdown on dissent.
Sumption said Hong Kong's rule of law had been "profoundly compromised" and the city was "slowly becoming a totalitarian state".
The number of foreign judges on Hong Kong's Court of Final Appeal (CFA) has fallen from about 13 to five in recent years, with some raising concerns at the imposition of a sweeping national security law.
In his statement to Reuters, French said he rejected any suggestion that foreign judges serving on the CFA were "somehow complicit in the application ... of national security laws or somehow confer on them a spurious legitimacy".
Hong Kong's chief justice is allowed to select one foreign judge - typically retired top jurists from the UK, Australia and Canada - to serve on the five-person Court of Final Appeal at any one time.
