Local media said one of two people arrested was Tommy Yuen, a former member of Cantopop boyband "E-Kids".

A police source confirmed to AFP that Yuen was among those arrested.

Yuen had been largely out of the spotlight since E-Kids, a pop trio known for their brightly coloured hair and catchy tunes, disbanded in 2004.

But he became an outspoken advocate for democracy protests that convulsed Hong Kong in 2019 and have since been silenced with a crackdown on dissent.

Steve Li, a senior superintendent of Hong Kong's national security police department, announced that two men aged 41 and 20 had been arrested on Tuesday afternoon.

Li would not confirm the identities of those arrested which is standard practice by Hong Kong police.

But he said the 41-year-old was a singer and that the other arrested person was a relative. Yuen is 41.

Outlining the police's case, Li accused the 41-year-old singer of "inciting" Hong Kong residents to hate the city's government as well as to try and change the political system.

One example he raised was an online live concert by the singer last year that allegedly contained the phrase "Liberate Hong Kong Revolution of Our Times", a once popular democracy slogan now declared illegal.

"He sang it because he wanted to incite Hong Kong residents to change Hong Kong's system via some unlawful means," Li said.

Li also cited social media posts critical of the government and alleged that the singer had raised some HK$1 million ($128,000) in donations "to help fellow protesters" arrested during the protests.

China is currently remoulding Hong Kong in its own authoritarian image using both a sweeping national security law imposed by Beijing and sedition, a once little-used British colonial era law.

Yuen is the second Hong Kong pop star arrested by national security police in the past three months.

In December Denise Ho, a much more prominent pop star and LGTBQ compaigner, was arrested for sedition along with journalists at a now shuttered online news platform. She was later bailed.

Both Yuen and Ho backed the democracy movement and last year found themselves unable to find venues willing to host their concerts.