TOKYO—Toyota Motor Corp. said Friday that disruptions at component suppliers will prevent a resumption of full production at its global factories until November at the earliest.

Acknowledging the enormity of the challenge facing the Japanese auto industry, President Akio Toyoda said production at Toyota’s domestic plants would remain at about 50% of normal capacity through July, while production outside Japan would be at just 40% through August.

Japan’s big auto industry has been hobbled since a March 11 earthquake and subsequent tsunami devastated parts of its northeast coastal, home to 1,000s of big and small automotive-parts makers.

“The damage touched the economy, the whole of Japan and all businesses,” Mr. Toyoda said at a suddenly announced press conference in Tokyo. “It’s been very hard to see what’s around the next corner.” Continuing aftershocks in the region have led to unforeseen production setbacks in recent weeks, he said.

Toyota expects output to begin to rise in mid-summer so that prequake production capacity at all factories—and for all its models—is reached by November or December. Toyota’s deep reliance on these companies, supplying everything from electronic chips to specialized resins, is little different from its Japanese rivals, which have led the global auto industry in concentrating purchasing on fewer but higher quality suppliers.

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