Seiji Maehara, vice president of the Democratic Party of Japan, went on the attack Wednesday, calling Prime Minister Taro Aso a "con man" and "tax thief" and stirring up the Lower House Budget Committee.

Maehara chose to go after Aso on road-related tax revenues. Aso originally said that ¥1 trillion of the levies should be allocated to local governments without restrictions on use. But that money is now apparently going to be used mainly for road public works projects. Freeing up road-tax revenue was decided by Aso's predecessor, Yasuo Fukuda.

"From my point of view, you, Prime Minister Aso, are a habitual offender of 'Yaru-Yaru' ('Will do, Will do') fraud," Maehara said, playing on the notorious 'Ore, ore' ('It's me, it's me') fraud used to trick people into sending money to strangers.

"You say you will hold an election and you don't. You say you will free up the road-related taxes and you don't. This is nothing but fraud," Maehara said, triggering a screaming match between the ruling bloc and the opposition parties.

Seishiro Eto, Lower House Budget Committee chairman, warned Maehara to refrain from rude statements. But Aso appeared unfazed and brushed off the insults with a smile.

"Fraud is a crime. We must both be careful and tone down our words," said Aso, who is known for verbal gaffes. "I understand how you feel, but fraud is a criminal offense."

When Aso refused to answer Maehara's question, the latter became irritated.

"That is complete nonsense. If that is the kind of answer you are going to give, you might as well just go home and sleep," Maehara said. "You should be ashamed of yourself. . . . You are a tax thief!"