The government on Friday approved bills to revise criminal proceedings to make police and prosecutors obligated to record interrogations, to introduce a plea bargaining system and to expand the scope of wiretapping.

It wants to pass the bills before the Diet closes in June, but legal experts and lawyers have criticized the proposed amendments as insufficient enough to prevent false charges.

The bills oblige investigators to keep audiovisual records of the entire interrogation process for those held in cases subject to lay judge trials, including murder and robbery resulting in death, or cases dealt with by prosecutors' special investigation squads, including economic crimes and corruption.

But such cases only account for about 3 percent of the total.

The bills seek to introduce two patterns of plea bargaining.

The first is for economic and certain other crimes in which prosecutors would agree to not indict or to withdraw an indictment if the suspect or defendant gives evidence on a crime committed by accomplices or others.

In the second, witnesses will be spared responsibility if they gave testimony to their own disadvantage in trials.

The bills also call for expanding the range of cases in which investigators can wiretap phones and email by adding nine more types of crimes including murder, arson and robbery.