Japan's opposition is readying a no-confidence motion against Prime Minister Naoto Kan.
A vote on the motion was to be held in parliament on Thursday.
Kan, who became prime minister just a year ago, has been criticized for delays in construction of temporary housing for evacuees, lack of transparency about evacuation information, and a perceived lack of leadership.
On Wednesday, the largest opposition group, the Liberal Democratic Party, submitted the no-confidence motion along with two smaller opposition groups. The motion would force Kan to order the resignation of his Cabinet or dissolve the 480-seat lower house for elections.
The March 11 earthquake and tsunami left 24,000 dead or missing and caused the worst nuclear crisis since Chernobyl in 1986.