While hailing China’s “determination to help save Africa’s elephants from extinction”, Lo warned that in the four-year window between the mainland ban and Hong Kong catching up, Chinese sellers could move stocks across the border for sale in the city. But she said the recent news was still cause for optimism.

“With China’s announcement, now three of the world’s largest domestic ivory markets – that is China, Hong Kong and the US – are being phased out.”

Watch: China to ban ivory trade by end of 2017

Late on Friday, Beijing announced plans to shut down its ivory trade by the end of 2017 in a move designed to curb the mass slaughter of African elephants.

The mainland will end the processing and sale of ivory and ivory products by the end of March, according to a statement.

Earlier this month, the Hong Kong government announced a three-step plan to phase out the local ivory trade by the end of 2021, with a proposal to go before the legislature in the first half of next year.

But local ivory sellers said a ban within five years was unfair to licensed traders who must sell off the remainder of their legal stock.

The city still has some 70 tonnes of legal ivory on the market out of the original 700 tonnes registered when a 1989 ban on international trade came into effect.

So Chi-keung, president of the Hong Kong and Kowloon Ivory Manufacturers Association, said most of those stocks were large, ornate and expensive carvings that were hard to sell.

“How did they calculate that we will be able to sell all our stock in five years?” he said.

Aili Kang, Asia director for the New York-based Wildlife Conservation Society, said the mainland’s latest decision was a game changer for Africa’s elephants.

“We call on all other countries with legal domestic ivory markets to follow China’s lead and close their markets as well.”