The Democratic Party of Japan submitted a censure motion Tuesday against Financial Services Minister Heizo Takenaka.
The party blames Takenaka for injecting nearly 2 trillion yen into the ailing Resona banking group and allegedly helping window-dress the bank's capital adequacy ratio.
The largest opposition party also blamed Takenaka for defending Financial Services Agency Commissioner Shokichi Takagi.
The commissioner allegedly tried to blackmail Tokio Marine & Fire Insurance Co. into consolidating with Asahi Mutual Life Insurance Co. in January 2002.
The motion, which will be put to an open vote during the House of Councilor's plenary session Wednesday, is expected to be voted down. The ruling triumvirate of the Liberal Democratic Party, New Komeito and New Conservative Party have agreed to vote against it to defend the Koizumi Cabinet.
But the ruling coalition's stance against the motion is likely to put some ruling lawmakers into a somewhat difficult position, as they have vocally called for the immediate resignation of Takenaka.
The financial services minister, a symbol of Koizumi's economic reform policies, has been under fierce attack by key members of the LDP calling for more government spending and the protection of small firms dependent on loans from financial institutions.
Takenaka is also minister in charge of economic and fiscal policies.
The DPJ urged the other three opposition parties to join it in submitting the motion, but they declined, saying the motion has little prospect of passing the Upper House.
Even if it makes out of the Upper House, the censure motion has no legally binding power. This is because Cabinet members are chosen by the prime minister, who is elected by members of the House of Representatives.