A former vice-chairwoman of the Basic Law Committee, Maria Tam, says it is not a punishment to deny a sentence remission to those jailed for national security offences if it is believed they would pose a risk if released early.

Writing in Sing Tao Daily, Tam said it is not an absolute right for inmates to receive a reduction to their prison term, and it makes sense for them to be released only after they have served their entire sentence.

Her comments come after Ma Chun-man, who was jailed for inciting secession, reportedly did not receive an early release following the enactment of Article 23 security legislation.

"These new rules are not punitive measures. They do not increase the length of sentences, nor do they lead to illegal detention and affect human rights," Tam said.

Separately, Albert Chen, a law professor at the University of Hong Kong and a member of the Basic Law Committee, said people do not need to over-estimate the effect the new security ordinance will have on their daily lives.

"Although I think the regulation is wide-ranging and relatively strict, I estimate that... it will be relatively rare that prosecutions are initiated under the Safeguarding National Security Ordinance," he wrote in Ming Pao on Thursday.

Chen said people do not need to worry, for example, about inadvertently obtaining national secrets through unlawful means, as long as they do not bribe officials or pry in order to steal such information.

He added that people who have connections with organisations endangering security will not break the law if they cut ties with them after their operations are prohibited by the authorities.