China's export limits on rare earth conform with the rules of the World Trade Organization (WTO), said China's former WTO representative Sunday.

China had imposed regulating measures on the mining, manufacturing, processing and exporting of rare earth, limiting both exports and supply to domestic companies, Sun told Xinhua.

"According to WTO rules, a country's regulation on a certain product to avoid resource exhaustion and environment pollution should be applied to both exporters and domestic users, and supply to both foreign and domestic markets should be cut," said Sun.

As the world's largest rare earth producer and exporter, China provides more than 90 percent of global rare earth demand, though its reserves account for only one-third of the world's total.

Sun called for the diversification of the supply of rare earth and expressed hopes that rare earth importers seek the resource from other countries.

He said China was willing to conduct technological cooperation with other rare earth producing countries.