China's regulations do not violate WTO rules on origin, which calculate the origin with added-value, said Mei Xinyu, a trade expert with the Chinese Academy of International Trade and Economic Co-operation, a think tank with the Ministry of Commerce.

"Although the WTO prohibits obligatory rules on the proportion of imported products, it does not ban certain tariffs," he said.

China's imports of vehicles and spare parts were valued at US$13.6 billion last year.

This is the first time China has faced a dispute with the EU at the WTO and the second time with the United States the first being on semiconductors.

The case is one among several disputes between China and the United States before President Hu Jintao's visit to the country, including intellectual property rights, the trade surplus and the yuan rate.