TOKYO: Japan's ruling conservative party suffered a crushing defeat in elections Sunday as voters overwhelmingly cast their ballots in favor of a left-of-center opposition camp that has promised to rebuild the economy and breathe new life into the country after 54 years of virtual one-party rule, media projections said. The opposition Democratic Party of Japan was set to win 300 of the 480 seats in the lower house of parliament, ousting the Liberal Democrats, who have governed Japan for all but 11 months since 1955, according to projections by all major Japanese TV networks. The vote was seen as a barometer of frustrations over Japan's worst economic slump since World War II and a loss of confidence in the ruling Liberal Democrats' ability to tackle tough problems such as the rising national debt and rapidly aging population. National broadcaster NHK, using projections based on exit polls of roughly 400,000 voters, said the Democratic Party was set to win 300 seats and the Liberal Democrats only about 100. Official results were expected early Monday. As voting closed Sunday night, officials said turnout was high, despite an approaching typhoon, indicating the intense level of public interest the hotly contested campaigns have generated. The loss by the Liberal Democrats would open the way for the Democratic Party of Japan, headed by Yukio Hatoyama, to oust Prime Minister Taro Aso and establish a new Cabinet, possibly within the next few weeks. It would also smooth policy debates in parliament, which has been deadlocked since the Democrats and their allies took over the less powerful upper house in 2007. "The ruling party has betrayed the people over the past four years, driving the economy to the edge of a cliff, building up more than 6 trillion yen ($64.1 billion) in public debt, wasting money, ruining our social security net and widening the gap between the rich and poor," the Democratic Party said in a statement as voting began Sunday. "We will change Japan," it said. The Democrats have also said they will make Tokyo's diplomacy less U.S.-centric. But Hatoyama, who holds a doctorate in engineering from Stanford University, insists he will not seek dramatic change in Japan's foreign policy, saying the U.S.-Japan alliance would "continue to be the cornerstone of Japanese diplomatic policy." Hatoyama's party held 112 seats before parliament was dissolved in July. The Democratic Party would only need to win a simple majority of 241 seats in the lower house to assure that it can name the next prime minister. "We don't know if the Democrats can really make a difference, but we want to give them a chance," Junko Shinoda, 59, a government employee, said after voting at a crowded polling center in downtown Tokyo. With only two weeks of official campaigning that focused mainly on broadstroke appeals rather than specific policies, many analysts said the elections were not so much about issues as voters' general desire for something new after more than a half century under the Liberal Democrats. The Democrats are proposing toll-free highways, free high schools, income support for farmers, monthly allowances for job seekers in training, a higher minimum wage and tax cuts. The estimated bill comes to 16.8 trillion yen ($179 billion) if fully implemented starting in fiscal year 2013. Aso — whose own support ratings have sagged to a dismal 20 percent — repeatedly stressed his party led Japan's rise from the ashes of World War II into one of the world's biggest economic powers and are best equipped to get it out of its current morass. But the current state of the economy has been a major liability for his party. Last week, the government reported that the unemployment rate for July hit 5.7 percent — the highest in Japan's post-World War II era — while deflation intensified and families have cut spending because they are insecure about the future. Making the situation more dire is Japan's rapidly aging demographic — which means more people are on pensions and there is a shrinking pool of taxpayers to support them and other government programs.