KAWASAKI, Japan -- Decisions to build a network of Japanese highways have become so entangled in political deal-making they seem to ignore the public interest, analysts say.

Around two-thirds of the population are against constructing new highways, many of which are built in the countryside where usage is low, according to a recent newspaper survey.

However, 240 lawmakers from Japan's three ruling parties formed a group in July to promote building more roads.

"Road construction projects are decided essentially under the table among lawmakers, steelmakers and construction companies," said UBS Warburg's political analyst Shigenori Okazaki.

"A real problem is that in Japan, people have never had serious discussions about this. There has never been any attempt by lawmakers or taxpayers to make bureaucrats explain the reality of road projects," he said.

Four public corporations which build and manage expressways are collectively buried under 40 trillion yen ($341.9 billion) in debt, while 27 of Japan's 40 toll highways continue to accumulate massive losses and remain chronically under-used.

These grim figures were only made public by Japan Highway Public Corp. last month after pressure from a new advisory panel to Prime Minister Junichiro Koizumi.

Undaunted, the government still plans to build 2,300 kilometers (1,437 miles) of highways, which will require 20.6 trillion yen in additional investment.

"An assumption is that the roads will pay for themselves by collecting tolls. But most of them will be in areas where traffic volume is light," said Akihiko Suzuki, urban development analyst at UFJ Research Institute.

"Realistically, they will become bad loans and the government will have to use tax-payers' money to fund roads that essentially nobody uses. That's why the public is wary about new highway projects," he said.

Officials decide where to build new expressways based on need assessments, demographic changes and expected gross domestic product, among other "objective indicators", said a spokesman for Japan Highway, the largest of the four government-supported road-building companies.

But analysts argued bureaucrats use limited data to justify projects that have already got the green light from politicians and contractors.

Support from such people with vested interests keeps highway officials protected despite public disapproval of their huge spending and inefficient management, analysts added.

One notorious example is the $11-billion Tokyo Bay Aqua Line, the world's longest undersea road tunnel attached to a bridge that runs above water.

The expressway, which opened in 1997, is only used by about 13,000 motorists a day, fewer than a third of an initial government estimate made to justify the project.

Japan highway still expects traffic on the Aqua Line to rise above 40,000 per day by 2020, although Japan's population is expected to peak in 2006.

"It tells you how arbitrary their demand forecast figures are," said celebrated journalist Naoki Inose during a meeting of the prime minister's Special Advisory Panel.

The seven-member group is tasked with studying privatization of the four public highway corporations. But staunch opposition from old guard politicians from the ruling Liberal Democratic Party has made its work difficult.