The nation's public works projects -- notorious for their lack of transparency -- have sucked up tens of trillions of yen in taxpayers' money for decades, pushing government coffers to the brink of crisis.

The government forecasts that the outstanding public debt for local and central governments will reach 693 trillion yen in March 2003.

One reason for the projects' exorbitant costs, construction industry sources recently revealed, is that pricing data on construction materials that the national and local governments use to compile public works budgets are often set higher to benefit manufacturers and construction companies.