The secretary for labour and welfare said on Friday that he hopes an investigation by an operator of a care home into alleged abuse there could help prevent cases in future.

A care home worker of Hong Chi Association was arrested on suspicion of sexually assaulting two residents while on duty. The association has terminated the employee and promised its own probe.

"I hope Hong Chi Association's independent review committee can complete its work as soon as possible, look into details if any improvements can be made systematically, and ensure that such unfortunate incidents won't happen again in the future," Chris Sun said on an RTHK radio programme.

He also said the government is not in a position to offer details of abuse cases reported from four other care facilities, citing privacy concerns.

Sun added that the Social Welfare Department has issued warnings to 15 care homes in the past year.

"A warning letter is intended to inform care homes of any shortcomings, or if it's suspected of breaking the rules. We have to warn them. But the public has to understand that the warnings cannot include all the details.

"So we've always adopted a similar practice in issuing warning letters. The main point of doing so is to notify care homes of inappropriate actions and shortcomings. This can also allow the industry to know that they have to focus on a certain area and step up their efforts in this regard."

The Social Welfare Department will review the licence of the care home operated by Hong Chi Association annually in the wake of the case, instead of the current practice of every three years.

Sun said the department's next move depends on the findings of the independent review committee.

"The operation of a care home depends on its quality and whether its operations are up to the required standard. That's one thing. But if someone does bad things for an ulterior motive, that's mostly down to the individual. The two things have to be separated," he said.