The Chinese buy much of the world's elephant ivory
The UN has given China the green light to bid in a one-off sale of ivory.
The Convention on International Trade in Endangered Species (Cites) voted in favour of China's request during a meeting being held in Geneva.
China joins Japan as approved buyers of government-owned ivory from South Africa, Botswana, Namibia and Zimbabwe.
In 2007, Cites authorised the four nations to sell off stockpiles of legally held elephant ivory.
In order to gain approval, China had to present evidence to members of the Cites standing committee that it had put in place measures to tackle any illegal domestic sales of ivory.
"China has acted rather successfully against its own illegal domestic ivory market," said Tom Milliken, a director for Traffic, the wildlife trade monitoring network.
"Now China should help other countries to do the same, especially in central Africa where elephant poaching is rampant."
But Robbie Marsland, UK director for the International Fund for Animal Welfare (Ifaw), condemned the decision, saying it could prove disastrous for the world's elephant populations.
"We are deeply disappointed that Cites has backed China as an ivory buyer, a decision that plays Russian roulette with wild elephants.
"Allowing new ivory to be imported into China will stimulate demand and create a smokescreen for illegal ivory to be laundered into the legal market, to be sold in stores or online to Chinese citizens or foreigners."
However, Mr Milliken said Cites monitoring systems would track whether the sale would lead to an increase in illegal ivory.
"Following the last one-off ivory sale under CITES in 1999, it is encouraging to note that the illicit trade in ivory progressively declined over the next five years," he explained.
"We hope a similar result is achieved this time."
Under an agreement reached in 2007, Cites gave permission for the four nations to make a single sale of all government-owned stocks of ivory that have been registered by January of that year.
South Africa declared the largest amount, making 51 tonnes available, while Botswana's stockpile was almost 44 tonnes. The other two countries declared much smaller amounts; Namibia total was just under 10 tonnes, and Zimbabwe stockpile was almost four tonnes.
In March and April, the Cites secretariat conducted audits in each of the four nations to ensure the ivory had been properly registered and had been obtained legally.
The 2007 agreement also stipulated that once the one-off sale had been completed, no further sales from these countries would be considered during a "resting period" of nine years that would begin as soon as the new sales had been completed.