Wrapping up campaigning in what is expected to be one of the most heated elections in years, Abe told a crowd of thousands in central Tokyo: "We will move forward with reforms and improve the economy."

"There is no way the Democrats and other opposition parties can push through reforms," he said, rolling up his sleeves and speaking in a voice hoarse from a campaign that has failed to reverse his dismal poll ratings.

His own seat in the more powerful lower house is not up for election, but analysts and polls suggest voter dissatisfaction with him could spill over and lead to the ousting of candidates from his long-ruling Liberal Democratic Party.

Ichiro Ozawa, whose opposition Democratic Party of Japan has benefited from a series of scandals that have tarred Abe's government, said, "This is a truly important election that will determine the future of Japan. I am staking my life on this election."

Though leaders were stumping in different locations, their messages to the voters were pretty much the same their opponent can't be trusted to run the government.

Setting up what is expected to be a very close battle, one-half of the seats in the 242-member upper house of parliament will be contested on Sunday. Polls suggest the ruling party headed by Abe may face difficulty maintaining its majority over the fast-rising Democrats, Japan's main opposition party.