A Justice Ministry panel on Monday began reviewing what critics call Japan¡¯s lax criminal penalties against rapists and other sex offenders, in the nation¡¯s first comprehensive effort in more than a century to overhaul laws on sex crimes.

The panel of outside legal experts is tasked with discussing ways to revamp sex offense statutes that have remained untouched since their enactment in the Meiji Era, save a few minor changes.

During the first session of its deliberations Monday, the panel discussed whether to make sex crimes such as rape and indecent assault prosecutable without a complaint being filed by a victim, the Justice Ministry said.

Critics have long argued that victims tend to refrain from initiating legal action themselves, either because they are ashamed to come forward or are misguidedly convinced they are somehow at fault for what happened. This is often true even when their tormentors are family members, such as parents and siblings, critics say.

Most panel members agreed that no complaint by the victims should be deemed necessary to prosecute such crimes, a Justice Ministry official told reporters.

Other topics to be deliberated by the panel include raising the minimum sentence for rapists from the current three years to five years ¡ª equivalent to crimes such as murder, robbery and arson. While rape resulting in injury or death currently entails at least five years in prison, and a maximum of life, the panel will also consider increasing the minimum to six years.

It will also debate updating the definition of rape, which the law currently stipulates as referring only to an assault against women in the form of vaginal intercourse.

One possibility, the ministry said, is to make rape applicable to both male and female victims and inclusive of acts such as anal and oral sex.

Furthermore, the panel will look into the possibility of setting up a new penalty against rape committed by offenders who have taken advantage of their ¡°guardianship¡± over children under the age of 18, such as parents, in a bid to curb incestuous abuse.

The move to review criminal penalties against sex crimes was originally spearheaded by Midori Matsushima, a former justice minister who, upon assuming the post in September 2014, declared that harsher penalties for sex offenders was a centerpiece of her policy agenda.

After wrapping up the discussions, the panel will submit recommendations to the ministry so it can compile amendment proposals.