National security police on Thursday laid holding charges against a man, 59, with one count of doing an act or acts with seditious intention and one count of uttering seditious words, and a woman, 67, with one count of uttering seditious words.
The pair will appear at the West Kowloon Magistracy on Friday morning.
The other four were freed on bail and have to report back to the police in early May.
Police did not name the six people who were arrested, but according to media reports one of them is Leo Tang, former vice president the now-disbanded Confederation of Trade Unions.