Lawmakers will once again be asked to pass legislation making it illegal to participate in plotting a serious crime, such as murder, regardless of whether the crime is ever committed, a government source said.

Since 2003, the government has made several attempts to revise the organized crime punishment law, citing its obligation under an international treaty signed in December 2000 to fight cross-border organized crimes.

Each time it has met fierce opposition from critics such as the Japan Federation of Bar Associations and opposition lawmakers who fear such legal provisions could be used to clamp down on activists and labor unions. All of the legislative attempts ended up being scrapped.

In addition to the treaty obligation, the government this time sees the need for a legal framework for devising counterterrorism measures ahead of the 2020 Tokyo Olympics, the source said Tuesday.

In the wake of the Diet passing the state secrets law last week to crack down on leakers of information the government at its discretion decides to deem classified, critics fear a conspiracy offense law could allow the state to exert excessive control over the privacy and activities of citizens.

The Justice Ministry has said the revision is intended to crack down on organized attempts by gangsters to commit murder and on organized fraud by racketeers.

The secrets law also incorporates a clause that makes the act of conspiracy punishable even if no crime is actually committed.