Japan Automobile Manufacturer’s Association chairman Toshiyuki Shiga confirmed all nine Japanese carmakers with plants in Thailand had been forced to stop production this week.
Mr Shiga said Honda, Mazda, Mitsubishi, Nissan and Toyota were among the worst affected by the floods.
"As a whole, production of 6000 units has been affected on a daily basis," he said."Of the nine companies which have halted plants, eight have done so because they could not procure parts sufficiently."
Honda suspended production at its HATC Ayutthaya plant between October 4 and 8 because of parts supply disruptions, and reclosed the factory on October 10 as the floodwaters reached the plant property.
At the time, Honda Australia confirmed major deliveries of new vehicles from Thailand were on their way to meet local customer orders.
At this stage, it remains unclear how long each carmaker’s production facilities will remain out of action.
Mr Shiga, also the CEO of Nissan, said a number of manufacturers were weighing up shifting production and sourcing parts from factories in Japan or other countries while the floods continued.
Thailand acts as a second manufacturing home for a number of Japanese carmakers. In 2010, 1.6 million Japanese-brand vehicles were produced in the southeast Asian country.