The opposition vows to slash public works spending if it wins the election. Keeping that promise may be tough in a nation where construction is the No. 5 employer and a political fundraiser.

Government outlays on dams, roads and bridges have been a source of stimulus since the bubble economy burst two decades ago. Infrastructure spending amounted to 4.4 percent of gross domestic product last year, extending a binge that has driven public debt to almost twice GDP, or ¥16.4 million for every household.

The Democratic Party of Japan says much of that money cements ties between builders, bureaucrats and government officials and it pledges to spend less on construction. Yasuo Tanaka, a DPJ-supported candidate in Sunday's election who canceled public projects as governor of Nagano Prefecture, says the population isn't well served.