LEGAL trade in rhino horn will cause even more black-market activity, an animal activist group said on Tuesday.

"Whenever you have a restricted market where only certain people can buy and sell, then you will always encourage black-market activity," said Allison Thomson, director at Outraged SA Citizens against Poaching, a non-profit organisation.

So far this year, 251 rhinos have been poached in South Africa. The sale of rhino horn, some believe, will remove the black-market trade and therefore decrease the level of poaching.

Responding to the notion of legalising rhino trade to curb poaching, Ms Thomson said: "The models that are put forward for trade are based on economically flawed assumptions."

By opening up trade, she said, the number of consumers would exceed the supply of rhino horn. An increase in demand would also not necessarily reduce the price of rhino horn. As rhino horns are rare, the possibility of poaching would therefore increase.

Ms Thomson said possible trading partners for South Africa would not contribute to the country's efforts to conserve the rhino.

"Trading partners that exist in the illegal trade at the moment are China and Vietnam ... it is clear we would be getting into bed with partners that have no wildlife trade management tools in place," she said.

"It would spell disaster for our rhino to enter into trade in horn with countries that have little to or no incentive themselves to save our rhino," Ms Thomson added.

In May, the Department of Water and Environmental Affairs said it would explore the possibility of introducing trade in rhino horn ahead of the 16th congress of the Convention on International Trade in Endangered Species (Cites), expected to take place in Thailand in March next year.

However, a proposal would not be made until the following Cites meeting, the department said.

Edna Molewa, minister of water and environmental affairs, said there were too many legal obstacles for South Africa to make a considered proposal to Cites next year.