The Japanese government told an international body last summer that it intends to enact a law that will allow it to crack down on anyone even slightly involved in a terrorist plot, sources said.
In December 2000, Japan signed a U.N. treaty aimed at fighting global organized crime. However, bills aimed at punishing not just those who commit crimes, but those who only take part in plotting them, have since been defeated in the Diet.
The stalemate led to a visit from the Financial Action Task Force, an inter-governmental body set up by the G-7 in 1989 that develops and promotes policies to combat money laundering and terrorist financing, in August 2013.
At that time, Tokyo told the FATF delegation that it would speed up efforts to develop anti-terror legislation, a government source said Saturday.
The FATF's plenary meeting is scheduled to be held from Feb. 9 to 14 in Paris, where Japan is expected to explain its plans to fight money laundering and terrorist financing. But Tokyo will stop short of going into details on how to deal with conspiracy charges.