Secretary for labour and welfare Chris Sun on Sunday defended plans to mandate certain government subsidy recipients to do voluntary work, saying it is a way of helping them integrate into society.

Sun was referring to a new Social Welfare Department pilot scheme, which will make it compulsory for unemployed Comprehensive Social Security Assistance (CSSA) recipients aged 15 to 59 to take up at least one hour of unpaid work each week.

He noted 16,000 CSSA recipients are healthy adults capable of working, and hoped that the scheme can motivate them to start looking for a job.

"We don't want CSSA recipients to feel like they are out of touch ... We think the most viable way is to ask them to do volunteering work. This is achievable and there's a great social need for this kind of work," Sun told reporters after attending a charity event.

On a separate note, the labour chief also expressed great concern regarding two fatal industrial accidents on Friday.

One case involved an 18-year-old apprentice, who fell into an escalator shaft in Central.

The other fatality was a 57-year-old painter, who died after being trapped on a spider lift platform while working at a Tung Chung public housing construction site.

The Labour Department has issued suspension notices to the contractors involved, and is investigating the accidents.

"The probe will focus on whether the two sites complied with the necessary work procedures. Everyone knows there are clear guidelines for both escalator maintenance and the use of lift platforms," Sun commented.

He also stressed the need to step up promotion and education efforts.

"We hope that whenever an accident occurs, other workers in the trade can raise their safety awareness and sense of responsibility ... The government, employers, employees and relevant stakeholders should all work towards this goal."