The global conference that governs wildlife trade voted Monday against proposals by Namibia and Zimbabwe to be allowed to sell their ivory internationally, in a move welcomed by many conservationists.
Namibia and Zimbabwe — which boast healthy elephant populations — had lobbied for the right to sell off stockpiles accrued from natural deaths and poaching seizures to fund projects in communities close to elephants.
"(The meeting) votes in committee against proposals of Namibia and Zimbabwe to allow international commercial trade in their elephants," the Convention on International Trade in Endangered Species (CITES) said in a statement at its conference in Johannesburg.
International trade in ivory has been banned since 1989, but legal domestic markets have continued in some countries around the world, and CITES has twice allowed sales of African ivory stockpiles to Japan and China, in 1999 and 2008.
In the two secret ballots, the proposals by Namibia and Zimbabwe were heavily defeated.
"African elephants are in steep decline across much of the continent due to poaching for their ivory, and opening up any legal trade in ivory would complicate efforts to conserve them," said Ginette Hemley, head of the WWF delegation at CITES.
"It could offer criminal syndicates new avenues to launder poached ivory, undermining law enforcement, and would undercut efforts to reduce the consumer demand that is driving the mass poaching."
She welcomed the votes on Monday, and urged nations to concentrate on closing domestic ivory markets and combating the illegal international trade.
A recent census showed a 30-per cent decline in the savannah elephant population over seven years, and new data released by wildlife monitor traffic showed a "rising trend in large raw ivory shipments" last year.
A coalition of 29 African countries is pressing for all African elephants to be given an Annex 1 CITES listing, which bans all international trade, but other delegates believe this would fuel the booming illegal market.
The conference in Johannesburg, which ends on Wednesday, is sifting through 62 proposals to tighten or loosen trade restrictions on around 500 species.
Delegates at the weekend adopted a recommendation aimed at clamping down on domestic ivory markets "contributing to poaching or illegal trade".
Illegal trade in wildlife is valued at around $20 billion (18 billion euros) a year, according to CITES.
Vietnam, a key consumer of rhino horn, has faced severe criticism at the conference, which is held every three years.
The CITES treaty, signed by 182 countries and the European Union, protects about 5,600 animal and 30,000 plant species from over-exploitation through commercial trade.
Delegates have already voted to ban all international trade in African grey parrots, one of the world’s most trafficked birds, and in shy, scale-covered pangolin.