TOKYO, Dec 28 (Reuters) - Japan's top oil refiner JX Nippon Oil & Energy Corp said on Monday it would refine 1.11 million barrels per day (5.49 million kilolitres) of crude oil in January for domestic consumption, down 2 percent from a year earlier.

Its December crude refining for domestic consumption was estimated at 1.09 million bpd (5.35 million kl), down 5 percent from the year-earlier period, and slightly below the original plan of 1.11 million bpd (5.45 million kl) due to some problems with the secondary units, a company spokesman said.

(Reporting by Osamu Tsukimori; Editing by Michael Perry)