The Japanese company has been producing ethylene at a reduced rate at its plant in Kamisu, Ibaraki Prefecture, northeast of Tokyo, since Friday, the officials said.
The decision reflected concerns that naphtha, a material for ethylene, could be in short supply amid escalating tensions in the Middle East.
Mitsubishi Chemical has already notified its major clients of the production cut.
Japanese petrochemical firms make ethylene at 12 domestic production facilities using naphtha.
Ethylene is used to make a wide variety of industrial products, including resin, auto parts, synthetic fibers and food packaging.
Japan relied on about 60 per cent of its naphtha supply on imports as of 2024, about 70 per cent of which came from the Middle East, according to the Japan Petrochemical Industry Association.
Among other Japanese petrochemical makers, Idemitsu Kosan Co. has notified clients that it could suspend operations at ethylene facilities in Chiba Prefecture, east of Tokyo, and Yamaguchi Prefecture, western Japan, if the effective closure of the Strait of Hormuz is prolonged.
Mitsui Chemicals Inc., which makes ethylene at plants in Chiba and Osaka Prefecture, western Japan, is considering increasing naphtha purchases from suppliers other than the Middle East, a company official said.
[Copyright The Jiji Press, Ltd.]