Lawmakers on Tuesday expressed support towards the government's plans to expand checks on sex offender records to gradually cover the self-employed, volunteers and existing workers.

The current system allows voluntary checks on prospective employees seeking jobs related to children and the mentally incapable, meaning the employer needs the consent of the job-seeker to perform the check.

Officials now want the scheme expanded in the fourth quarter of this year, first covering self-employed persons such as sports coaches, music teachers and tutors.

By the end of next year, the scope would expand to cover volunteers, and eventually at an unspecified date, all existing employees.

At a Legco security panel meeting, legislators said they supported the plan, saying it was necessary to better protect children and the mentally challenged.

Legal sector lawmaker Ambrose Lam asked whether the SAR would follow the UK system, known as the Sarah's Law, under which parents can seek records on a person who can come into contact with their children.

He noted that in Hong Kong, parents sometimes ask a friend to help pick up their children from school, and the SAR should be forward-thinking in preventing potential abuse.

However, security chief Chris Tang dismissed the idea, saying the two places are different.

"In Hong Kong this is too broad a scope. At the moment, friends would not be included under this [expanded] scope," he said.

Others expressed concern the expanded scheme would add more work for the police force, and that people who sought the checks would have to wait for a long time at police stations.

A number of lawmakers, including New People's Party's Dominic Lee, asked if officials could handle the applications electronically, such as using the government's iAM Smart mobile app.

However, Tang said the app cannot replace the stringent checks on the conviction records required, because it involves fingerprints of all fingers and thumbs.

The minister added that officials would conduct loading tests before the new system is up and running, which is capable of handling more than 210,000 new applications a year. Last year, there were around 83,000 ongoing requests.

He said six police stations planned to set up designated kiosks, allowing people to have their fingerprints collected throughout the day to help speed up the process.