More than 80 Liberal Democratic Party members support a leadership vote to challenge unpopular Prime Minister Taro Aso ahead of the general election this year, the campaign's organizer said.

Taku Yamamoto, a four-term Lower House member, said he expects to get "a lot more" support if LDP candidates lose the Tokyo Metropolitan Assembly election July 12. He needs about 220 lawmakers and local party leaders on board to force a leadership ballot.

Aso's approval ratings have plummeted following the resignation of internal affairs minister Kunio Hatoyama and last month's election by the Democratic Party of Japan of a new leader to replace the scandal-tainted Ichiro Ozawa. One newspaper survey this week showed the DPJ has twice the voter support of the LDP-New Komeito ruling coalition.