South Africa has signed a deal with Vietnam to tackle rhino poaching in a bid to crack down on the illegal trade in horns for use in traditional medicine.

South Africa's department of environmental affairs said the agreement, a memorandum of understanding, included conservation and protection provisions, as well as a pledge to increase law enforcement efforts and information-sharing between the two countries.

"We believe that this latest development at an international level is crucial for South Africa to effectively deal with the scourge of poaching, and with illegal hunting largely driven by the international demand for the rhino horn," said minister Edna Molewa.

In 2012, 618 rhinos - South Africa's "national treasure", according to Molewa - have been slaughtered, compared to 448 in 2011 and 13 in 2007.

"South Africa is looking forward to receiving the close co-operation from Vietnamese partners to stop the illegal trade of rhino horns," she said.

Vietnam's minister of agriculture, Cao Duc Phat, said that fighting wildlife crime "especially on the rare, precious and endangered species including rhinos, [is] always of concern to the Vietnam government".

He said the southeast Asian country had started to put more resources into stopping the illegal horns trade.

The deal, which is partly a result of heavy lobbying by animal rights activists, covers cooperation in biodiversity management and conservation and refers only in general terms to addressing illegal wildlife smuggling.

Traffic, a wildlife trade monitoring group, identified Vietnam as the main destination for illegal rhino horn in its August 2012 report.

"The world's rhino populations are hanging by a thread, and today the opportunity was taken to throw them another lifeline," Naomi Doak, coordinator of Traffic, said.

"Rhino poaching is a burning conservation issue and through the public commitments of the two governments we have seen promising beginnings of collaborative action. This commitment now needs to be turned into urgent action to turn the crisis around."

WWF and Traffic welcomed the deal as a "turning point" in efforts to protect Africa's rhinos.

"South Africa and Vietnam have publicly signalled their intention to get tough on the criminal syndicates behind the rhino poaching spree," said Stuart Chapman, WWF-Greater Mekong conservation director.