China has been given a yellow score by the World Wildlife Fund (WWF) for failure to effectively supervise its internal ivory trade and track the sale of legally-imported ivory.

The report selected 23 African and Asian countries that have the highest level of illegal trade in ivory, rhino horn and tiger parts, and gave them scores of green, yellow or red to evaluate the progress made for each species.

China received a yellow score in the trade of elephant tusks, warning that compliance and enforcement have to be strengthened.

Green cards are offered to China in the trade of tiger and rhino parts after the government moved to curb the illegal trade in these species.

The report said that "China is the only country evaluated that allows internal ivory trade under a control system," but "failed to effectively police the system and track the sale of legally-imported ivory."

In 1991, the Chinese government prohibited the export of ivory products. In 2004, China introduced the ivory product registration and certification system to control the domestic ivory market and regulated that only government-approved ivory processing and retail outlets are allowed to engage in the ivory trade. It also set an annual cap of five tons for the consumption of ivory.

China is one of only two approved buyers of government-owned ivory from South Africa, Botswana, Namibia and Zimbabwe, which was approved by the Convention on International Trade on Endangered Species.

"The existence of a legal ivory market provides loopholes for smuggled ivory, because retailers can smuggle ivory under the cover of the legal domestic market," said He Yong, a spokesman for the China branch of the International Fund for Animal Welfare (IFAW).

The IFAW's 2011 survey of China's ivory markets found that illegal ivory trade was taking place in legal facilities and most licensed facilities "violated the system in some way to launder illegal ivory."

"The ever-appreciating values of ivory and huge profits are the strongest motives for ivory traders," a representative from WWF Beijing Office surnamed Sun told the Global Times.

"Chinese collectors and investors considered ivory products as 'white gold' and believe that ivory can help with exorcising evil spirits. Ivory is also a traditional medicine, which provides another incentive for Chinese buyers," Sun added.

An ivory product can sell for as much as 5 million yuan ($785,400) at auction, prices that bring more retailers into the ivory trade, according to the IFAW survey.

"The government has been making great efforts to control the ivory trade," Wan Ziming, head of the National Endangered Animals Management Office's law enforcement department was quoted by greentimes.com as saying.