The Chinese and English names as well as the residential addresses of the voters were stored in those files, but not their identity card numbers, dates of birth and genders, according to the office.

“The staff member concerned has been immediately deployed away from her existing duty,” the office said in a statement published Friday night, and added the case has been reported to police.

Preliminary investigation revealed that the staffer did not follow the departmental guidelines as she intended to send those files to her personal email address on Wednesday night. Yet, she entered an incorrect email address and sent the files to an unknown recipient.

“The REO has immediately notified the recipient concerned via email to permanently delete the relevant files at once and contact the REO for follow-up,” it continued.

The office apologized to voters involved and said the incident has also been reported to the Office of the Privacy Commissioner for Personal Data and the Office of the Government Chief Information Officer.

“The REO will remind all staff members to comply with the departmental guidelines, exercise due care in handling personal particulars related to electors and not to send any files containing those particulars to personal email addresses,” it said.

The office also said they will stringently follow up on and further investigate the incident. A comprehensive review of the incident and appropriate improvement measures will be in place as well to prevent similar incident from happening again.