The Public Security Investigation Agency filed a request Monday with the Public Security Examination Commission to keep Aum Shinrikyo under surveillance for another three years.
The surveillance period is set to expire in January.
The agency requested the extension on the grounds that cult founder Shoko Asahara, who stands accused of masterminding the 1995 sarin gas attack on the Tokyo subway system and another deadly nerve gas attack the previous year, "still wields power over the cult" and can order indiscriminate mass killings.
The commission will determine in early January whether to extend the period after studying the contents of the request, including the reason the agency gave for filing it, and hearing opinions from Aum on the matter.
The focus will be whether the cult still poses a threat to the public and is capable of committing mass murder. The commission is expected to make its decision around early January.
The cult has made it clear it will file a lawsuit against the surveillance if the extension is authorized.
In August, Aum filed a petition with the security agency, demanding it cancel its plan to keep the cult under surveillance for another three years. The cult also filed a petition with the committee in November requesting that it no longer be subject to surveillance, claiming it no longer poses a public threat.
Acting under the powers of the current surveillance authority, the agency has kept 88 Aum facilities in 16 prefectures under watch since January 2000.
The agency also decided to file the petition on the grounds that high-ranking cult members, including Fumihiro Joyu, who were senior members at the time of the 1995 Tokyo subway attack, are still active.
The agency alleged that the cult maintains a secret doctrine ordering followers to kill, and said members still attempt to justify the sarin attacks.
Asahara, 47, whose real name is Chizuo Matsumoto, has been on trial since April 1996 for allegedly ordering the subway attack of March 20, 1995, which killed 12 people and injured thousands, the June 1994 sarin attack in Matsumoto, Nagano Prefecture, that killed seven and injured hundreds, and a raft of other major crimes. He has pleaded innocent to all counts.
Justice Minister Mayumi Moriyama said she expects the commission to make a speedy and appropriate examination of the issue.
The Tokyo District Court in June 2001 dismissed a lawsuit filed by the cult that demanded an end to the surveillance.
But the court acknowledged the cult's claim, saying it is "difficult to admit that Matsumoto is still a member of the cult, and there is no evidence that his doctrine is still maintained within the cult." It added that the continuation of the surveillance should be decided after carefully examining all aspects of the situation.
Aum spokesmen expressed their opposition to the agency's move Monday, saying the cult, which has renamed itself Aleph, has no potential to commit another indiscriminate mass attack.
"The agency fell short of presenting evidence to prove our danger or whether (Asahara's) influence on us could lead to another mass murder," said Shigeru Sugiura, an Aum spokesman during a news conference at the district court.
In supporting their claim, the cult members said they believe Asahara no longer has the will and power to direct the cult to commit more crimes. But they also said the guru still has a "purely religious" influence over them.