The Public Security Intelligence Agency requested the Public Security Examination Commission on Monday to extend the surveillance period of two religious groups originating from the Aum Supreme Truth cult for another three years before the current period expires at the end of January.
The agency said it made the request because the groups are increasing their assets and members still have strong faith in Aum founder Chizuo Matsumoto, a 59-year-old convict on death row.
The commission plans to make a decision on the agency's request by the end of January after hearing opinions from the groups.
If the request is approved, it will be the fifth extension of the surveillance.
In the surveillance, which started in 2000, the agency can conduct on-site inspections on the groups' facilities. The groups are also required to report the names and other information on their members to the agency regularly.
The Aum Surpreme Truth has split off into the mainstream group Aleph and another group named "Hikari no Wa" (the Circle of Rainbow Light) headed by Fumihiro Joyu, 51.
According to the agency, the two groups have a total of 32 facilities in 15 prefectures with about 1,650 members, of which 1,450 belong to Aleph.
They also have about 160 followers in Russia. Compared to the figures of three years ago when the last extension request was made, the members increased by about 150 in the nation and about 20 in Russia.
More than 60 per cent of the nation's increase comprises young people under 35.
Aleph reportedly has been attracting people in various ways such as organising a yoga circle and events such as parties exclusively for women, which look unrelated to the religious groups, and inviting participants via social networking services.
The groups' assets, including cash and deposits, stand at 650 million yen (S$7.17 million) in total. They have increased about 17 times from about 38 million yen in 2000.
With major income sources such as donations from members and participation fees for seminars, the assets are said to have increased by 80 million yen annually for the past few years.
In the latest extension request, the agency also pointed out Matsumoto's third daughter, 31, has been recognised for the first time as an executive member of Aleph.
The agency said the daughter is involved in the decision-making process of the group because she holds talks and exchanges letters with senior members of the group.