The opposition camp used Tuesday's Diet session to issue fresh demands for both Prime Minister Yukio Hatoyama and Democratic Party of Japan Secretary General Ichiro Ozawa to be grilled over their political money scandals.

"We are seeing an unprecedented situation," Liberal Democratic Party Secretary General Tadamori Oshima told the Diet, referring to the arrests of former secretaries of both Hatoyama and Ozawa in connection with illegal transfers by their funding management organizations.

Oshima demanded that the Diet call on those involved in the scandals, including Ozawa himself, to give a full account of the irregularities.

New Komeito policy chief Tetsuo Saito criticized Hatoyama's handling of unregistered donations from his mother, saying the prime minister's payment of more than ¥500 million in gift taxes after the incident came to light does not cancel out the wrongdoing.

"This was clearly tax evasion," Saito said.

Hatoyama kept his guard up to parry further thrusts.

"I take the criticism seriously," Hatoyama told the Diet but added that the investigation by prosecutors on the funds from his mother has been concluded without further charges.

His "duty" now is to answer the calls from the public and work toward bringing the change in government that the DPJ promises, he said.