A House of Councilors panel has proposed reducing the voter disparity in Upper House representation by shifting four seats to the populous Tokyo and Chiba prefectural constituencies from less populated areas, according to panel members.

But the change would only narrow the gap in the voting weight ratio of the least populated district to the most populous from 5.06-to-1 at present to 4.76-to-1.

The Supreme Court ruled the weight of votes in the 2001 Upper House election was not unconstitutional but may decide the weighting is unconstitutional in the next poll if the disparity increases.

All parties with seats in the chamber have agreed in principle to make reforms through amendments to the Public Offices Election Law by the next Upper House election is held in the summer of 2007, the panel members said Wednesday.

An advisory panel subcommittee to House of Councilors President Chikage Ogi, made up of representatives from all parties, has proposed moving two seats each from the Tochigi and Gunma constituencies to the Tokyo and Chiba districts, they said.

The two-seat increase would bring the number of Tokyo seats to 10 and that of Chiba to six; the cuts for Tochigi and Gunma would leave them with two seats each.