Japan's economic output ran above full capacity in April-June for the first time in nearly four years, a government estimate showed, suggesting that conditions for ending its policy of ultralow interest rates could be falling into place.

The output gap, which measures the difference between an economy's actual and potential output, grew 0.4% to mark the first increase in 15 quarters, according to Friday's estimate.

Prime Minister Fumio Kishida said the data was significant but added that the margin of increase remained small and that whether the trend could be maintained was key.