Toyota Tianjin plant [file photo]

"The tense Sino-Japan relations has affected sales of Toyota automobiles in China, and it is a common practice for a company to adjust production volume based on market demand and orders," said the spokesman.

At a sales outlet of Toyota in Tianjin, customer numbers have decreased by 30 percent. Some have withdrawn or postponed orders.

Tensions between the two countries have risen since early September, when Japan announced plans to purchase part of the Diaoyu Islands in the East China Sea.

Beijing has maintained the islands are part of China's inherent territory.