Prime Minister Taro Aso embarked Friday on the new task of delivering on a ¥56.8 trillion economic stimulus package, again leaving the key question of when he might dissolve the Lower House and call a snap election up in the air.

Aso's move, which follows a recent swing in political fortunes due to opposition chief Ichiro Ozawa's fundraising scandal, unleashed a new wave of speculation over when the general election, which must be held by fall, will be called.

Some political observers said one option for Aso and his Liberal Democratic Party is to dissolve the Lower House in May for an election, while the Democratic Party of Japan struggles with the fallout of the indictment of Ozawa's top aide, Takanori Okubo, over shady political donations from Nishimatsu Construction Co.