TOKYO (Reuters) - Fuji Heavy Industries Ltd <7270.T>, a first-tier supplier for Boeing Co's 787 passenger jet, said there was no change to its production plans for the grounded Dreamliner's wingbox.

"Our production plans are unchanged," said Mitsuru Takahashi, Fuji Heavy's chief financial officer at a quarterly earnings news conference on Wednesday.

Boeing has halted deliveries of the 787 until the cause of battery fires is uncovered by investigators in Japan and the United States, but is still assembling new planes in the U.S., keeping the completed jetliners at its plants.

Fuji Heavy, better known as a maker of Subaru cars, is the sole maker of the 787's wingbox, a critical component that connects the wings to the fuselage.

(Reporting by Yoko Kubota and Tim Kelly; Editing by Ian Geoghegan)