Mining production increased 6.3% on the month in May, while output in the manufacturing and energy sectors advanced 2.5% and 1.8%, respectively.
The data are adjusted for the number of working days and seasonal factors.
In annual terms, industrial production increased 13.3% in May, reflecting growing output in most sectors.
Manufacturing and mining output rose 15.5% and 7% on the year, respectively, but energy production inched down 0.8%, the data showed.
In unadjusted data, Romanian industrial production rose 3.2% on the month in May, and was up 12.5% compared with the same month of 2013.