TOKYO: Japanese online retailer Rakuten Inc said on Friday it was banning the sale of ivory on its site, shutting a major sales route in one of the world's largest legal ivory markets.

The company made the decision following mounting international criticism of the trade, a Rakuten spokesman said, with trading to be phased out over the next month.

While China has pledged to shut down its domestic ivory trade by the end of this year, ivory imported before 1989 can be legally traded in Japan, with the government denying a link to illegal poaching.

Both the government and e-commerce sellers have been tightening monitoring of sellers, who are legally required to register their stock, amid criticism from wildlife groups that not enough is being done to prevent rule breaking.

Ivory trading continues on Yahoo Japan, the country's biggest online auction site.

"We don’t think that the legal ivory trade in Japan has any impact on African elephant numbers," said a Yahoo Japan spokesman.

"It is important to recognise there are cultural differences between different countries," he added.

Elephant numbers fell 30 percent between 2007 and 2014, according to a census funded by Microsoft co-founder Paul Allen, with illegal poaching thought to be the primary reason for the decline.

The WWF says about 415,000 African elephants remain today, compared with the 3 million to 5 million in the early 20th century. The animal is listed as a vulnerable species by the International Union for Conservation of Nature.