A court hearing involving some of Hong Kong's best known dissidents was adjourned in the early hours of Tuesday after one of the 47 defendants charged with subversion fainted and was rushed to hospital.

The hearing, which began on Monday, sparked a resurgence of public defiance in Hong Kong unseen in months as hundreds of pro-democracy supporters gathered outside the courthouse to chant and flash protest symbols.

Activists, like Mike Lam pictured here, presented themselves at Hong Kong courts on February 28 to face charges of committing subversion
Activists, like Mike Lam pictured here, presented themselves at Hong Kong courts on February 28 to face charges of committing subversion AFP / ISAAC LAWRENCE

The dissidents were charged Sunday with conspiracy to commit subversion -- the broadest use yet of China's sweeping security law imposed on the city last year. It criminalises any act considered to be subversion, secession, terrorism or collusion with foreign forces.

Court proceedings stopped around 1:45 am Tuesday local time when defendant Clarisse Yeung appeared to faint and collapsed.

Hundreds of protesters, some chanting slogans including "Release all political prisoners" and "Liberate Hong Kong, revolution of our times", queued up outside the law courts in one of the biggest gatherings in months
Hundreds of protesters, some chanting slogans including "Release all political prisoners" and "Liberate Hong Kong, revolution of our times", queued up outside the law courts in one of the biggest gatherings in months AFP / Anthony WALLACE

Magistrate Victor So later announced that the hearing was adjourned until 11:30 am local time.

The defendants will be held by the Correctional Services Department, while the two hospitalised defendants will be under police custody, he said.

Large numbers of police stood guard outside the West Kowloon court in Hong Kong during court appearances by dozens of dissidents
Large numbers of police stood guard outside the West Kowloon court in Hong Kong during court appearances by dozens of dissidents AFP / Anthony WALLACE

As the court adjourned, the defendants rose and gave a round of applause to their lawyers.

Beijing is struggling to quash dissent in semi-autonomous Hong Kong after huge and sometimes violent pro-democracy demonstrations in 2019.

Police are freely using China's national security law to crack down on dissent, while thwarting demos by invoking a ban on public gatherings of more than four people designed to help stop the spread of the novel coronavirus.

Mike Lam was among dozens of activists who presented themselves in court in Hong Kong on February 28 to face charges of committing subversion
Mike Lam was among dozens of activists who presented themselves in court in Hong Kong on February 28 to face charges of committing subversion AFP / ISAAC LAWRENCE

Nevertheless hundreds of pro-democracy demonstrators met outside the law courts to show their support for the dissidents.

Some chanted slogans including "Release all political prisoners" and "Liberate Hong Kong, revolution of our times" -- the latter a slogan authorities have deemed illegal under the security law.

Key points of China's recently imposed national security law for Hong Kong.
Key points of China's recently imposed national security law for Hong Kong. AFP / John SAEKI

Many flashed the three-finger "Hunger Games" salute that has been embraced by fellow democracy campaigners in Thailand and Myanmar.

Police raised banners warning that an illegal gathering was taking place and that protesters' chants were breaking the national security law.

Key points of China's recently imposed national security law for Hong Kong.
Key points of China's recently imposed national security law for Hong Kong. AFP / John SAEKI

Officers later dispersed the crowd outside the courtroom citing Covid-19 restrictions. The demonstrators largely complied, with some heckling officers and chanting as they left.

A pro-democracy supporter displays a placard outside the West Kowloon court in Hong Kong as dozens of dissidents are charged with subversion
A pro-democracy supporter displays a placard outside the West Kowloon court in Hong Kong as dozens of dissidents are charged with subversion AFP / Peter PARKS

Local district councillor Kwan Chun-sang was one of dozens who camped overnight to bag a spot at the front of the queue for the court's public gallery.

"Soon after the charges were laid yesterday I decided to come and spend the night here," he told AFP. "I would like to show my support for the pro-democracy activists."

A small group of pro-Beijing protesters held banners welcoming the subversion charges.

"Punish the traitors severely, enact the national security law and throw them all behind bars," one sign read.

The defendants represent a cross-section of Hong Kong's opposition, from veteran former pro-democracy lawmakers to academics, lawyers, social workers and youth activists.

So many have been charged that officials had to open up three other courtrooms to accommodate the overspill.

The alleged offence for those facing subversion charges was organising an unofficial primary last summer to choose candidates for the city's legislature, in the hopes that the pro-democracy bloc might take a majority and block government legislation.

Chinese and Hong Kong officials said this was an attempt to "overthrow" the city's government, and therefore a threat to national security.

The dissidents were arrested in a series of dawn raids in January and charged on Sunday with "conspiracy to commit subversion" -- one of the new broadly defined national security crimes. They face up to life in prison if convicted.

US Secretary of State Antony Blinken led international criticism of the latest charges, calling for the group's immediate release, as western powers accused Beijing of shredding the freedoms and autonomy it promised Hong Kong could maintain ahead of the territory's handover from the British.

Britain and the European Union said the charges showed the law was being used to target political dissent rather than threats to national security.

China's foreign ministry on Monday dismissed the criticism, saying Beijing "resolutely supports Hong Kong police... in upholding national security as well as Hong Kong's security and stability".

Those charged under the law can expect to be held for months until their trial, as the law removes the territory's tradition of granting bail for non-violent crimes.