A US computer security expert has decided to sue the Japanese government after, he claims, it censored him at a recent security conference.

Ejovi Nuwere, chief technology officer of SecurityLab Technologies, is suing the government for violation of his freedom of speech under Article 21 of the Japanese Constitution. It is the first of its kind in Japan, according to his lawyer.

Nuwere claims that officials of Japan's Ministry of Internal Affairs and Communications (MIC) forced him to abandon a presentation he was due to give earlier this month on security issues related to Japan's online citizen registry network, called Juki Net.

Juki Net is a national network of databases that contain the names and personal details of nearly every person residing in Japan, and has been surrounded by controversy, particularly over its security.

During a security audit conducted last year, Nuwere and Japanese experts managed to compromise servers in part of the system maintained by one of Japan's prefectural governments. He was due to talk about those experiences at the conference.

Nuwere claims he was forced to cancel his talk after MIC officials demanded that he remove a series of slides and not voice his conclusions about the audit. The revisions imposed on the talk were drastic, and amounted to censorship, he said.

Calling the MIC's actions an unacceptable act, Nuwere said he was filing the suit with the aim of preventing public authorities in Japan committing a similar injustice. "The MIC has no right to tell any one citizen or non-citizen that they cannot speak," he said. "We should all be entitled to think and speak our own opinion, free from government oversight," he said.

Nuwere said he felt he should file the suit because the MIC did little or nothing to resolve disagreements about the contents of the speech, despite offers by Nuwere to meet with officials to reach an agreement. "What they did was censorship in its most basic form," he said.

The government will probably respond with a counter-petition in about a month or six weeks, according to Shimizu. The plaintiff will then decide whether or not to reply, and the case will probably go to court, said Shimizu. If or when this happens, legal proceedings will probably take more than a year.