Japan on Thursday passed its biggest-ever budget, a $937 billion spending package aimed at propping up growth as consumers brace for the country's first sales tax rise for over 15 years. "The most important policy of the Abe government has been and will be to restore a strong economy," Prime Minister Shinzo Abe told a news conference after the passage of the budget for the fiscal year beginning on April 1. "We will try to minimise the negative impact of the increase in the consumption tax." A total of 136 lawmakers in the 242-member upper house, controlled by the ruling Liberal Democratic Party, voted for the package, against 102 opposition votes, a parliamentary spokesman said. Two lawmakers did not cast a vote, one seat is vacant and the house speaker only casts a ballot in a tie. The lower house last month approved the 95.88 trillion yen ($937.4 billion) budget. The new budget comes as Tokyo pushes for speedy implementation of a $50 billion stimulus package specially designed to protect Japan's fragile economic recovery, as the sales tax rises to 8.0 percent from 5.0 percent on April 1 -- the first increase since the late 1990s. The increase is seen as crucial to bringing down Japan's eye-watering national debt, which is proportionately the worst among rich nations. But there are fears it will derail Abe's policy blitz, dubbed Abenomics, aimed at kickstarting the world's third-largest economy after it suffered years of growth-denting deflation. "It is our national project to bring Japan out of deflation," the premier said. "With the passage of the budget, we showed to people at home and abroad a strong determination on the part of our parliament to end deflation." Abe swept to power in late 2012 on a ticket to rescue Japan's long-lumbering economy. The budget -- up from 92.61 trillion yen for the current fiscal year -- is seen as key to paying for Japan's snowballing health and social welfare costs. The rapidly ageing population is putting pressure on the public purse, while low birth rates are threatening to create a demographic time bomb for the heavily indebted nation. Japan's projected primary balance deficit -- the shortfall between what the government takes in and what it spends, apart from debt-servicing -- is expected to shrink by 5.2 trillion yen to 18.0 trillion yen. That means Japan's national debt, now more than twice the size of the economy, will continue to rise but at a slower pace. Public spending projects are part of the proposed budget as well as plans to upgrade Japan's defence forces, as China bulks up its military and fears remain over North Korea's nuclear arms potential.