Hong Kong Interior Minister Caspar Tsui has resigned, weeks after attending a birthday party for a Hong Kong delegate to China's national legislature during the coronavirus restrictions, DW reported.

The party was held on 3 January at a restaurant to celebrate Witman Hung's birthday. More than 200 people were in attendance, including top territorial police officials and the heads of the immigration and anti-corruption agencies and 20 deputies.

The list of those in attendance came to light after health authorities tracked down an infected person who was present. This was a source of outrage for Hong Kong's chief executive, Carrie Lam, whose government has a strict "zero-COVID" policy.

Photos of the party, leaked to local media, showed attendees singing karaoke and posing for group photos without masks.

Authorities said Tsui did not use a government app to track contacts when entering the restaurant, which is now mandatory. He also did not wear a mask.