TOKYO (Kyodo) -- Japan's domestic production of naphtha, an oil derivative necessary to make chemicals used in a wide range of products, fell 22.8 percent from a year earlier to 906,660 kiloliters in April, the industry ministry said Friday.

The Ministry of Economy, Trade and Industry said supplies remain sufficient because manufacturers have been drawing on inventories of chemical products derived from naphtha to offset the decline in domestic production.

According to preliminary petroleum statistics, imports of crude oil from outside the Middle East have increased following the de facto closure of the Strait of Hormuz, prompting refiners to operate facilities more cautiously to avoid processing troubles.

The government says supplies of naphtha-based products can be maintained into next year, but companies have voiced growing concern about procurement risks as disruptions linked to the Middle East situation continue.