The national debt exceeded ¥1 quadrillion for the first time, underscoring the case for Prime Minister Shinzo Abe to proceed with a sales tax increase to shore up government finances.

The country's outstanding public debt, including borrowings, reached a record ¥1.08 quadrillion ($10.4 trillion) as of June 30, up 1.7 percent from three months earlier, the Finance Ministry announced Friday. Larger than the economies of Germany, France and the U.K. combined, the amount includes ¥830.5 trillion in government bonds.

The world's heaviest debt burden will weigh on Abe when he has to decide next month whether to start the two-step plan to double the 5 percent tax on consumers in a nation with ballooning welfare costs. While boosting the levy will create a drag on growth, Moody's Investors Service warned Thursday that a worsening of government finances will "erode confidence in" JGBs.