Speaking on a radio program, Lau said the changes on the subject of Liberal Studies was "quite revolutionary," as teachers will no longer only teach students how to deal with tests.

When it comes to teachers' concerns about violating the National Security Law when teaching social topics, Lau said teachers should have the professional expertise to know how to teach the new secondary school subject.

He suggested the national security police can provide some public education, like the Independent Commission Against Corruption did, to help schools understand how to carry out their work without breaking the law.

Lau added that the revamped Liberal Studies should lessen teachers' pressure as there would be fewer assessments.

On Wednesday, authorities announced that the subject of Liberal Studies would be renamed "citizenship and social development" and introduced in September for Secondary Four students.

The curriculum of the revamped subject consists of three themes - Hong Kong, the nation and contemporary world -, covering topics like constitutional relationship between the SAR and China and the Basic Law.

Students will also have to go on a 10-hour mainland study trip, delving into the theme of "Chinese culture and modern life."