Other species under discussion at the meeting include the big leaf mahogany from the Amazon rainforest, grey and minke whales and brown bears from Europe and Russia.
In the 1920s there were only about 50 white rhinoceroses, one of two African species left in South Africa, as a result of persecution by big game hunters and poachers. Today there are some 7,000.
But the Natal national parks now have a stockpile which, like elephant tusks, cannot be legally traded because this is banned by the CITES treaty. There is, however, still a market for smuggled rhino horn which prices it at roughly $1,000 a kilogram. The South Africans say spending that kind of money on wildlife conservation could bring huge gains at a time when government budgets are under strain.
The debate over the horn is similar to that over the move by Namibia, Zimbabwe and Botswana to be allowed to trade their elephant ivory stockpiles with Japan.
Both proposals seem unlikely to get the two-thirds majority vote needed among the 140 CITES nations to get the go-ahead. But they, or similar requests, are bound to feature at future treaty meetings.
There is now widespread agreement between conservation groups and governments that wildlife has to be managed to be conserved. And that management must involve exploiting it in a way that benefits local communities, giving them an incentive to look after it. But there is passionate argument about whether that exploitation should consist only of encouraging overseas visitors to look at the wildlife, or include big game hunting and selling animal products abroad.
Since 1977, all five rhino species, the black and the white rhinos from Africa, and three from Asia, had been fully protected from any international trade under CITES. But an illegal trade continued and rhino numbers continued to fall until a few years ago, with the exception of the white.
At the last CITES meeting two years ago South Africa won an exemption to export live white rhinos for conservation purposes and to export hunting trophies from those big game hunters who legally shot it (having paid large sums for the privilege).
Now it wants to go further, and trade in rhino parts, though it would accept a "zero quota" initially, meaning no trade at all. But the proposal would establish South Africa's right in principle to export rhino products. The country says it has a right to do so, having shown it can conserve the species. Apart from the horns, it is interested in sales of rhino skin, valued in Oriental medicines used against skin ailments.
But conservationists say a resumption of legal trade would risk raising demand for rhino horn and the price, encouraging poachers in parts of Africa and Asia where other rhino species are still endangered. There are only about 70 Javan rhinos left.
"We'd have countries going back into business importing rhino products," said Dr Esmond Bradley-Martin, WWF's leading rhino consultant. Until a few years ago, Taiwan was the world's leading rhino horn importer. Butan investigation by the wildlife trade investigating body TRAFFIC earlier this year showed that Yemen, next to Saudi Arabia, was now the leading importer taking about 50kg a year.Reuse content