The six - aged between 32 and 67 - were picked up in their homes yesterday for acts suspected of breaching section nine and 10 of the Crimes Ordinance.

They were said to have "purposely caused nuisance" while attending hearings at courts including the high court as well as the West Kowloon and Eastern magistrates' courts between December and January.

It is understood they are also suspected of doxxing lawyers who prosecuted on behalf of the Department of Justice in social unrest cases.

"These acts severely affected jurisdictional dignity and court operations," officers said.

Armed with search warrants, officers also seized a number of items from the suspects' homes.

Apart from Tang, the other men arrested include government trade officer So Yat-kai who had previously been arrested during the social unrest, pastor Garry Pang and reporter Siew Yun-long.

The other two were women - Chiu Mei-ying and Lee Wing-kam.

Former Labour Party vice chairman Cheng Sze-lut said on Facebook yesterday that six officers entered Tang's home at 6am to arrest him.

"They alleged that Tang, on January 4 at West Kowloon magistrates' courts, incited other members of the public to disrupt court order, with the intention to bring hatred or excite disaffection against the administration of justice," Cheng said.

On the day in question, barrister Tonyee Chow Hang-tung was jailed for inciting others to join a banned June 4 vigil in Victoria Park.

During mitigation pleas, some Chow supporters had applauded, drawing contempt-of-court warnings.

The confederation and its former leaders have been embroiled in controversy throughout the year. In February, police had requested it hand over documents related to operations, income and expenses.

Additionally, Tang - along with two former confederation leaders Joe Wong Nai-yuen and Chung chung-fai - were brought in for questioning on March 31 over an alleged violation of the Societies Ordinance.