Indonesia is considering microchipping convicted child rapists after the brutal gang rape and murder of a schoolgirl sparked demands for tougher punishments, authorities said Friday.

The 14-year-old girl was set upon by a gang of drunken men and boys as she walked home from school on the western island of Sumatra.

Her battered body was found three days later in woods, tied up and naked. Seven teenagers, aged 16 and 17, were jailed this week over the assault, while five men have been arrested and are awaiting trial.

The attack happened in April but came to public attention this month when activists started posting about it on social media, and has sparked a national debate on sexual violence.

President Joko Widodo has pledged to swiftly push through a decree introducing tougher laws, and a justice ministry spokesman confirmed that one of the measures under consideration was for microchips.

Local media reported that the microchip could be implanted in rapists' ankles.

"The microchip will be fitted before the criminals are released from prison, and is needed to monitor and locate them after they are freed," said Asrorun Niam Sholeh, head of government-backed rights group the National Commission for Child Protection, who has been involved in discussions on the new laws.

The decree could be signed in the coming days, he added.

Chemical castration and heavier jail terms for child rapists are also among new measures that could be introduced.

The government announced last year it would begin chemically castrating child sex offenders after a string of high-profile attacks, but introduction of the punishment had been delayed.

A presidential decree allows the government to quickly bring in new laws without first getting parliament's agreement.

The schoolgirl case in Indonesia has drawn comparisons with the fatal gang-rape of a student on a bus in Delhi in 2012, which sparked mass protests and led to an overhaul of India's rape laws.