A conservative group within Japan's major ruling party on Wednesday finalized proposals to allow men from now-abolished collateral branches of the imperial family to rejoin it, as part of measures to ensure stable succession.

The proposals, to be submitted to Prime Minister Shinzo Abe, were crafted as the number of successors to the Chrysanthemum Throne continues to dwindle.

The 1947 Imperial House Law stipulates that only males of the patrilineage can ascend the throne. After the enthronement of Emperor Naruhito, the family now has only three heirs -- the emperor's younger brother, Crown Prince Fumihito, 53, his son Prince Hisahito, 13, and Prince Hitachi (Masahito), 83, the uncle of the emperor.

To sustain the imperial family, the group within the Liberal Democratic Party came up with ideas such as having unmarried male members of the former branches join the imperial family through adoption or marriage, if they want to. The group has suggested the creation of a law to enable this as an emergency measure, instead of revising the Imperial House Law.

Emperor Naruhito has a daughter -- Princess Aiko, 17, -- and there are other females in the family, but the Imperial House Law requires women to abandon their imperial status after marrying commoners.

(File photo shows tourists visit the Imperial Palace in Tokyo.)

The group is also against allowing women to remain imperial family members, even after marriage.

The proposals came after 59-year-old Emperor Naruhito proclaimed his enthronement on Tuesday before some 2,000 guests, including dignitaries from about 190 countries and international organizations.

He became Japan's 126th emperor on May 1, the day after his father, former Emperor Akihito, stepped down -- the first Japanese monarch to do so in about 200 years.

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