Wong, who is already serving a prison sentence for subversion, is one of the most recognisable faces of Hong Kong's now-quashed democracy movement.

The 28-year-old became a household name during student-led protests over a decade ago, and was also involved in the huge and sometimes violent democracy rallies that triggered the imposition of the 2020 national security law.

On Friday Wong was accused of asking foreign countries or individuals and institutions to "impose sanctions or blockade, or engage in other hostile activities" against Hong Kong and China, according to a charge sheet seen by AFP.

Wong, the now self-exiled activist Nathan Law and others also requested the foreign entities "seriously disrupt the formulation and implementation of laws or policies" in Hong Kong and China, it said.

These actions in 2020 were likely to cause "serious consequences", it continued.

The charge can carry a sentence of up to life imprisonment.

Wong appeared in court but did not speak except to acknowledge the charge, local media reports said.

The case was adjourned until August 8.

The national security law has seen the city's once vibrant civil society and political opposition all but vanish.

China and Hong Kong say the law was needed to curb political unrest, but rights groups and Hong Kong opposition figures say the ensuing crackdown has destroyed the city's autonomy and political freedoms.