The U.N. special rapporteur on the right to privacy has challenged the government's defense of the contentious law Japan enacted last June to criminalize the planning of serious crimes.

In a written reply to Kyodo News, Joseph Cannataci said the "shortcomings" of the government's arguments regarding his concerns about the respect of the right to privacy under the new state-sponsored law "would presumably be obvious to the most casual of observers."

Cannataci warned in a letter to Prime Minister Shinzo Abe in May that the conspiracy law could lead to undue restrictions on privacy due to its potentially broad application and a lack of privacy safeguards.