The Democratic Party of Japan's reluctance to participate in Diet proceedings or vote on some bills increased the likelihood that the ruling bloc will extend the extra Diet session beyond its Nov. 30 close.

The DPJ boycotted Upper House sessions Tuesday after DPJ leader Ichiro Ozawa failed to persuade Prime Minister Taro Aso, in an emergency meeting the night before, to submit the second supplementary budget for a Diet vote by Nov. 30 and pave the way for an early general election.

"Depending on (the DPJ's) attitude, the current Diet session should be extended," Aso told reporters in the evening, noting the importance of passing key bills.