Toyota plans to halt production next week at its biggest assembly plant in China, reports said Tuesday, with demand for Japanese cars slumping because of a bitter territorial row between Tokyo and Beijing.

Toyota, the world's biggest automaker in the first half of 2012, said it will suspend production for a week starting Monday at its Tianjin FAW plant in the country's northeast, the leading Asahi Shimbun reported.

The factory, one of nine Toyota plants in the country, accounts for about 60 percent of Toyota's China production, the report said.

A Tokyo-based spokesman for Toyota declined to comment on the Asahi report, saying "production adjustments are part of the company's normal practice and it does not disclose details of such adjustments".

Toyota and other Japanese automakers including Honda and Nissan have cut output in China -- the world's biggest vehicle market -- as sales plunge in the wake of a diplomatic row over a string of East China Sea islands controlled by Japan but claimed by China.

The chain -- known as Senkaku in Japan but called Diaoyu by Beijing -- are located in rich fishing waters and believed to sit atop vast mineral reserves.

The sovereignty dispute prompted tens of thousands of Chinese to protest last month, with some urging a boycott of Japanese products.

Japanese factories and businesses across China closed or scaled back operations in September over fears they or their workers could be targeted by mobs protesting against Tokyo's nationalisation of the islands.

Toyota earlier said production at its Tianjin FAW and Guangzhou-based GAC plants would be shuttered in the days leading up to and during a week-long national holiday in China at the start of October.

Together, the two plants produced about 770,000 of the approximately 800,000 vehicles that Toyota makes annually in China.

Japan's top three automakers have said their sales in China plunged last month, with Toyota seeing the biggest drop as September sales slumped 48.9 percent year on year to 44,100 vehicles.

Nissan tumbled 35.3 percent to 76,066 vehicles and Honda dropped 40.5 percent to 33,931 units.