Japan's industrial production waned in May, possibly raising challenges for the nation's central bankers and others trying to stimulate Japan's economic output.

Japan's industrial production index fell 2.4% on year in May, and declined a seasonally adjusted 0.1% from April, reported the Ministry of Economy, Trade and Industry (METI) on Monday.

Industrial shipments in Japan in May rose 2.4% on month, but fell 2.3% on year, added METI.

Industrial inventories fell 1.8% on month in Mya, and declined 3.1% on year, reported the agency.

The METI industrial bulletin was somewhat in line with a recent Japan manufacturing sector report, issued by S&P Global.

The headline Japan manufacturing purchasing managers index (PMI) rose to 50.1 in June from 49.4 in May, logging just above the 50-marker that separates growth from contraction, reported S&P Global earlier this month.

"The latest reading was therefore consistent with broadly stable operating conditions following an 11-month period of deterioration," said S&P Global.

Separately, Japan's tertiary (services) industry activity index rose 0.6% in May from the previous month, and gained 1.5% on year, driven by strength in transport, entertainment, and IT-related services, reported METI.

The Bank of Japan, the nation's central bank, meets at the end of July to reassess monetary policy. The Bank of Japan has forecast a modest 0.5% rise in the nation's gross domestic product (GDP) in the fiscal year started April 1.

Central bank officials will be expecting a slowing economy and a sluggish manufacturing sector, but also inflation rising too far above the Bank of Japan's 2% annual target.