Education Secretary Christine Choi said on Tuesday that teachers banned from the classroom for breaking the National Security Law or for mistreating pupils are unlikely ever to be allowed to return to the profession.

Appearing on an RTHK programme, Choi said new guidelines on teacher conduct would be released by the end of this year, setting out what is considered "fit and proper" for educators. She said whether teachers would receive a warning or face being struck off the register would depend on the circumstances of each case.

The minister said a task force would be set up to decide whether struck-off teachers could be allowed to return to the profession after showing improvement, but those whose disqualification was down to "poor moral conduct" were unlikely to be allowed back.

"If it's regarding their professional ability as a teacher, they can take some courses to prove themselves. But if they are involved in cases regarding poor moral conduct or they have caused damage to students, it's difficult for them to prove that they are suitable to be teachers again," she said.

Choi stressed that the authorities wanted to protect pupils from being bullied or insulted by teachers.

Asked about Monday's announcement that a requirement teachers to pass a test on the Basic Law and the National Security Law would be expanded, Choi said that even teachers whose subjects did not directly involve such matters should have this "basic knowledge".

Teachers taking up jobs at public schools have had to take the test from this school year, but the rule will be expanded in the next school year to new teachers at government-funded schools under the Direct Subsidy Scheme, as well as at kindergartens covered by the kindergarten education scheme.