Ten House of Councilors members from the ruling Liberal Democratic Party attended a meeting Thursday of the party's opponents to a set of postal privatization bills now before the chamber.
The 10 were among 58 LDP lawmakers who gathered at the first meeting of the opponents' group led by former House of Representatives Speaker Tamisuke Watanuki since the bills cleared the Lower House last week.
The bills would be rejected in the Upper House if 18 LDP members, coupled with all opposition lawmakers, vote against them -- a scenario that would mark a huge defeat for Prime Minister Junichiro Koizumi.
The Upper House began deliberations on the bills in a plenary session Wednesday and took them up Thursday in the Special Committee on Postal Privatization.
Watanuki's group gained momentum as 37 of its members voted against the bills in the Lower House and 14 others abstained from voting.
The bills cleared the Lower House with only a margin of five votes -- even though the LDP and its coalition partner, New Komeito, retain a comfortable majority in the chamber.
LDP lawmakers in the Lower House who voted against the bills, because they have vested interests in the state-run postal system, included four junior members of Koizumi's Cabinet -- two vice ministers and two parliamentary secretaries, who were removed from their positions immediately after the vote.
The 10 Upper House members who took part in Thursday's gathering included Takeaki Kashimura, parliamentary secretary for defense.