There are divided views on penalties for professionals who fail to report child abuse cases, with one lawmaker saying tougher punishments are needed to boost the deterrent effect.

Roundtable lawmaker Michael Tien made the comment a day after Legco passed the Mandatory Reporting of Child Abuse Bill, requiring 25 types of workers such as doctors and teachers to report suspected cases of serious harm.

Those who fail to do so will face a maximum punishment of three months in prison and a HK$50,000 fine.

But Tien, who cast the only abstention vote, said on an RTHK programme that he thinks the jail term should be extended to a year instead.

"In today's Hong Kong, a maximum penalty of one year in jail applies to most laws... What penalties are less than a year nowadays? Only for very trivial offences," he said.

"Seeing a child being continuously sexually assaulted and not saying anything is outrageous. When I think of the three-month jail term, I have nothing to say."

But speaking on the same programme, Federation of Trade Unions lawmaker Bill Tang said he believes the three-month maximum jail term is sufficient.

"Do higher penalties mean better social effects? I don't think so. A one-year jail term will make everyone feel scared and suspicious," he said.

Tang, who chaired the bills committee for the new legislation, said he hopes professionals will actively follow up on child abuse cases.