Japan's inventories of liquefied natural gas have surged since Russia's invasion of Ukraine, government data showed, in an effort to address concerns over potential disruptions of the biggest portion of fuel for power generation in the country.

LNG inventories in Japan stood at 5.9 million tons as of the end of August, up 17.6% from a year earlier and the largest since comparable data became available in 2008, according to the most recent data from the Japan Organization for Metals and Energy Security, a government agency.

Nine major Japanese utilities ramped up their combined LNG stockpiles 56% from a year earlier to 2.63 million tons as of Feb. 19. The volume is above their average stockpiles in the previous five years, according to data from the Natural Resources and Energy Agency.