Ichiro Ozawa, one of the country's most powerful lawmakers, rejected a request Friday to testify before a Diet ethics panel over his alleged role in falsifying a political funding report, setting up a possible showdown with Prime Minister Naoto Kan next week, ruling party lawmakers said.

Ozawa, a kingpin in the Democratic Party of Japan, told the party's secretary general, Katsuya Okada, that he finds "no rational reason" to appear before the Lower House political ethics panel, considering that his case will be addressed in court.

Ozawa's steadfast refusal is widely viewed as typifying the power struggle within the DPJ at a time when Kan, who heads the party, is faced with low approval ratings for his six-month-old government.

"I'm disappointed," Kan told reporters in Uruma, Okinawa Prefecture, about Ozawa's refusal. "Having heard about the situation from the secretary general, it would be better if I meet with Mr. Ozawa."

Okada and Ozawa, a former DPJ leader, held talks in the afternoon. Okada told reporters after the talks that he will arrange a meeting between Ozawa and Kan next week.

Okada reiterated Friday that the DPJ leadership will not hesitate to begin procedures to enable the ethics panel to adopt a resolution to summon Ozawa if he does not testify voluntarily. Ozawa, who is credited with the DPJ's rise to power in 2009, claims he has done nothing wrong.