China urged Japan on Wednesday "not to send wrong messages" to Taiwan and create new interference with China-Japan ties.
Foreign Ministry spokeswoman Hua Chunying made the remarks after an organisation set up by Taiwan changed its name from "The Association of East Asian Relations" to the "Taiwan-Japan Relations Association". A ceremony for the renaming was held on Wednesday.
Mikio Numata, a representative of the "Japan-Taiwan Exchange Association", attended the event.
Hua called the renaming a "plot together by the Japanese government and the Taiwan authorities" that "attempts to elevate actual ties between Japan and Taiwan".
Hua urged Japan to "stick to the one-China policy and take effective measures to correct its wrong action".
"There is only one China in the world. Taiwan is part of China," Hua said. "The Chinese government is resolutely opposed to countries that have set up diplomatic ties with it, maintaining official ties with Taiwan in any way."
The spokeswoman asked Japan to "effectively ob-serve the principles determined by the Sino-Japanese Joint Statement and promises it has made to China", and "not to send wrong messages to the Taiwan authorities and the international community".
Hua also warned Taiwan authorities that any attempt to create "two Chinas" or "one China, one Taiwan" will be "doomed to fail".