The House of Representatives approved a set of bills Thursday that toughen the penalties for heinous crimes and extend fixed prison terms to as long as 30 years.

The bills, passed by a plenary session of the Lower House, are expected to be passed during the ongoing Diet session after being approved by the House of Councilors.

Amendments to the Penal Code and the Code of Criminal Procedure will establish two new charges -- one for gang rape and another for gang rape resulting in death and injury. The amendments were made after a series of gang rapes involving university students in Tokyo came to light last year.

A Waseda University club called Super Free organized parties to attract women who wanted to meet men from prestigious universities and used this venue to rape women. The ringleader is appealing a 14-year prison sentence.

Revisions to the Penal Code call for lengthening the maximum prison term for a single serious crime to 20 years from the 15 at present. The maximum term for multiple serious crimes would be changed to 30 years from the current 20.

For a criminal whose sentence is commuted from the death penalty or life imprisonment due to a mental disorder or other reasons, the maximum prison term would be raised to 30 years from the present 15.