Toyota Motor on Monday halted all production at its factories in Japan due to a steel shortage following a blast last month at a steel plant.Assembly lines will be suspended for the rest of the week at 29 plants, including 18 operated by seven other companies within the Toyota group, a spokeswoman said. Operations are expected to resume on February 15, she said.The explosion at a steel plant operated by Toyota affiliate Aichi Steel in early January has made it difficult for the carmaker to secure enough of the particular type of steel it uses for its auto parts. Aichi Steel is not due to resume production until March 29.In the meantime, Toyota will obtain steel from other manufacturers, the spokeswoman said.The world's largest carmaker normally produces 13,000 to 14,000 vehicles a day in Japan.It is the first time Toyota has stopped all production in Japan since the 2011 earthquake and resulting tsunami in the north-east disrupted its supply chain.