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A Toyota Motors Tsutsumi factory worker assembles the Prius hybrid vehicle at the factory in Toyota city, Aichi prefecture, on June 35 2009. - 

STEVE CHIOTAKIS: A shortage of parts is again causing Japanese carmaker Toyota to halt operations at some of its plants. But the earthquake and tsunami in Japan happened more than a month ago. Shouldn't we have known about all the parts shortages by now?

From Tokyo, here's the BBC's Roland Buerk.

ROLAND BUERK: Auto parts are shipped around the world by sea. But huge container ships move slowly, so once parts get loaded on ships, they can take several weeks before they reach their final destination. Meaning, there were tons of parts already on ships and headed for factories around the world, before the tsunami stopped production in northern Japan.

It's those parts that have been supplying car factories for the past month and preventing shortages thus far. But now the parts shortages are hitting big auto firms like Toyota -- and that could carry on for a while.

Masahiro Itoh is a government official in northern Japan.

MASAHIRO ITOH: Many factories are repairing their equipment. The stocks are running out. It's difficult to meet orders from around the world. Economic losses are not yet clear, but the delay is problematic.

For Toyota, the shutdowns are a big blow. In Japan alone its suffered a production loss of a quarter of a million cars since the disaster -- and it says it isn't clear when it's going to be able to return to full capacity.

In Tokyo, I'm the BBC's Roland Buerk, for Marketplace.