The nation's factory output unexpectedly fell in March, the government said Friday, in a sign that gross domestic product is more likely to have shrunk during the first quarter.

Japan needs to see a healthy recovery in exports and industrial output ahead of a long-delayed sales-tax increase set for October. The Bank of Japan again highlighted the risks from the hike again on Thursday, in guidance on interest rates after its policy meeting, pledging to keep rates extremely low through at least spring 2020 in the face of "high uncertainties."

The nation's factory output slid 0.9 percent in March from a month earlier, compared with the median estimate of economists of no change, according to data from the trade and industry ministry. Production during the first quarter slid 2.6 percent from the previous three months for the biggest decline in nearly five years.