The Hong Kong authorities on Friday banned a former lawmaker who had been removed from office for improper oath-taking two years ago from running in a legislature by-election next month.

Lau Siu-lai, who won a seat in the 2016 Legislative Council election but was ousted along with five other pro-democracy legislators-elect after stirring controversy during oath-taking, called the government shameful for accusing her of not genuinely embracing China's sovereignty over Hong Kong.

A returning officer charged with confirming candidates for the by-election has invalidated Lau's nomination under the claim that advocacy for self-determination or independence is inconsistent with upholding the Basic Law — the mini-constitution in effect since the former British colony was returned to Chinese rule in 1997 — and makes it impossible to pledge allegiance to Hong Kong as required.