The Immigration Department has lost three notebook computers containing the personal data of 3,000 travellers. No Hongkongers are among the affected.
Officials suspected the computers, used in immigration control at Chek Lap Kok airport, had been stolen. The loss was reported on Wednesday, a department spokesman said.
The department reported to the police yesterday and set up a task force to review the security of all of its mobile devices that contained personal data, Secretary for Security Lai Tung-kwok said.
Lai said he was "very concerned" about the suspected theft.
Other computer systems in the department were unlikely to be affected as the missing computers belonged to a standalone network, the spokesman said.
As well, data on the devices had been encrypted and multiple authentications were required to log in to the network. "It is unlikely that the said data will be compromised," he said.
It was understood that the computers were located in an office room that would be locked whenever staff members left.
The devices contained the passport data of selected passengers in transit whose passports were scanned when they arrived. The network stores the data for a short period of time.
A preliminary assessment showed about 3,000 visitors were involved, but no Hong Kong passengers were affected, the spokesman said.
The department said it had notified the Privacy Commissioner for Personal Data of the data breach, and had implemented a series of measures to strengthen the security of the concerned computer network. It had also reminded its frontline workers to adhere strictly to the department's security guidelines, it said.
The task force, headed by the deputy director of immigration, was due to hand in a report to immigration director Eric Chan Kwok-ki in three months, giving recommendations to avoid a repeat of the incident.
Similar incidents have occurred in the disciplined services. Sheung Shui police station lost 79 permits of cross-border pupils in August, while a customs officer lost an unencrypted USB flash drive last year that contained more than 400 documents, some with suspects' details.