Toyota on Friday said it would extend a production halt in Thailand through October 22 due to parts supply constraints as a result of the country's worst flooding in decades.

Production at Toyota's three Thailand plants has been suspended since October 10, with the operations of many Japanese firms in the country crippled by the impact of massive inundations in recent weeks.

Japan's biggest automaker Toyota said that while floods have not directly impacted its Samrong, Gateway and Ban Pho plants, away from the worst-affected areas, "some suppliers are experiencing delays in supplying parts".

It said it would make a decision later on whether production would resume on October 24, depending on the supply chain situation.

Massive inundations have left hundreds dead across Thailand, Cambodia and Vietnam, with authorities stepping up efforts to reach victims of unusually heavy monsoon rains.

In Thailand the floods have damaged the homes or livelihoods of millions of people, particularly farmers, across about three quarters of the country's provinces.