The Correctional Services Department (CSD) said on Thursday it is looking into introducing legal amendments to prevent people placed under supervision from leaving Hong Kong.

A recall order was issued for Tony Chung, former convenor of the now-disbanded group Studentlocalism, after he allegedly violated his supervision order. He failed to return to the SAR from a trip to Japan in late 2023, and went to Britain to seek political asylum.

Chung had been sentenced to more than three-and-a-half years in prison in 2021 on secession and money laundering charges. He was released in June last year and placed under a year of supervision by the CSD.

The commissioner of correctional services, Wong Kwok-hing, said the case prompted the authorities to consider amending existing laws.

"According to current legislation, for all rehabilitated individuals under our supervision, if they want to leave Hong Kong, they are only required to inform our supervisors," he said.

"We don't have the right to ban them from leaving or entering the territory, so we are currently studying how we could improve on this front."

Wong also responded to reports that correctional officers had removed some newspaper contents before they were delivered to those behind bars.

"In fact, we only have one standard, that is, as long as contents of the books and publications sent to [correctional institutions] are not detrimental to the rehabilitation of anyone in custody, or have no impact on the order and discipline of the prison, we will allow these books and publications to be sent in," he said.

According to CSD figures, almost 17,300 people - either convicted, remanded in custody or detained - were newly admitted to correctional institutions last year, up by 30 percent from 2022. Some 950 individuals were put behind bars due to offences relating to the social unrest and the national security law.