Mainland authorities will soon have to inform the SAR government of detentions in no later than seven working days, and up to 30 working days for any Hong Kong resident suspected of terrorism or endangering national security, according to a new agreement.
Former Chief Executive CY Leung last year asked for a review of the notification system for detentions across the border after the SAR was not informed that Causeway Bay booksellers Lee Bo and Lam Wing-kee were being held on the mainland after their disappearances.
A statement released by the SAR government said an agreement on the new arrangement was signed in Beijing on Thursday.
"The notification mechanism is an administrative arrangement to be implemented on the basis of mutual respect for the relevant laws of both parties," a government spokesman said.
Under the new arrangement, Hong Kong and mainland authorities for the first time must inform the other side no later than seven working days after a detention, with this rising to no later than 14 working days for serious and complicated criminal cases. If terrorism or a national security risk is suspected, this can be extended to 30 working days.
Authorities have to state, among other things, where the suspects are being held and the detail of the alleged offences. The new mechanism will come into effect on February 1, 2018.
An agreement on such notifications was made in 2001, but there was no specific timetable for exchanging information.
Lee disappeared at the end of 2015 and it is widely suspected that he was abducted from Hong Kong by mainland security agents, although he later denied this. Lam said he was illegally detained in Shenzhen, with both men and three colleagues who also disappeared accused of selling illegal books on the mainland.