Customs chief Chan Tsz-tat stressed that safety takes priority for officers and they must hold themselves accountable for their actions.

A 27-year-old motorcyclist was killed last week in Kowloon Bay, after his vehicle rammed into an iron pole, and a 40-year-old man was later arrested on suspicion of tampering with a motor vehicle.

Customs earlier said it was a tragic incident, and confirmed that one of their officers was involved.

Speaking on a radio programme on Saturday, Chan said the case has been undergoing investigation and the involved frontline officer is now on leave.

Chan stressed that officers should contribute to society within legal and safe circumstances, and be responsible for every action even if they are not on duty.

"We have all along provided very comprehensive training for our staff members, starting from joining our department to on-the-job training, we have set very clear instructions," he said.

"Regarding the case, I must reiterate that safety is our primary consideration, no matter if a staff member is carrying out his duty in his official capacity or as a private citizen."