It looks like Prime Minister Yoshihiko Noda and his ruling Democratic Party of Japan are in for a rough ride in the current Diet session. The Liberal Democratic Party said Tuesday it is ready to submit censure motions against two Cabinet ministers.

LDP Secretary General Nobuteru Ishihara told a news conference the party will submit the motions to the Upper House against transport minister Takeshi Maeda and Defense Minister Naoki Tanaka as early as Wednesday.

New Komeito is set to support the motions, which are likely to be approved by the opposition-controlled Upper House.

Both Maeda and Tanaka have expressed their intention not to resign.

Although censure motions are not legally binding, the LDP is prepared to block Diet deliberations if the two ministers try to cling to their posts.

Maeda is under fire for signing documents soliciting support for a candidate in Sunday’s mayoral election in Gero, Gifu Prefecture, which the opposition force claims is a violation of the Public Office Election Law.

Maeda “says he didn’t know, but he signed it in his own handwriting,” Ishihara said. Maeda’s action “is extremely malicious and there is a very likely possibility that he violated the Public Office Election Law and we demand that he step down voluntarily.”

Tanaka meanwhile has revealed a lack of expertise in defense issues and most recently was criticized for the government’s slowness in informing the public of Pyongyang’s missile launch Friday. Tokyo’s announcement came 40 minutes after South Korea reported the launch at around 7:40 a.m.

Chief Cabinet Secretary Osamu Fujimura voiced support for Maeda and Tanaka. “I would like both ministers to fulfill their duties,” he said.

But some within the ruling DPJ-Kokumin Shinto (People’s New Party) coalition think Maeda should step down.

Kokumin Shinto Secretary General Mikio Shimoji reportedly said Tuesday that it would be difficult for the two ministers to stay in the Cabinet if the censure motions are adopted by the Upper House.

Maeda said Tuesday that he apologized to Noda for “causing trouble” after a Cabinet meeting.

“I’m deeply sorry for being careless (to sign without confirming the contents of the documents). Based on this, I’ll carefully fulfill my duties,” he said.

Tanaka also vowed to stay on. “I’ll make efforts each day by fulfilling my duties,” he said.

The documents Maeda signed were sent along with his name cards to a construction association in Gero prior to the filing of the candidates, asking for support for former DPJ Lower House member Yoshihiro Ishida.

The opposition claims this is considered a violation of the law. “(Whether this violates the election law or not) is a matter of interpreting the law. . . . But I never imagined the documents would be used like this,” Maeda said Monday evening.

“I’m taken aback by how they were used,” he said, adding he thought it was a letter encouragement, which are commonly sent to candidates.

According to Maeda, who has launched an investigation team involving a lawyer, a DPJ rookie member approached him and asked him to sign the documents. He is not particularly close to the DPJ member, he said.