Illegal killing of African rhinos is on the rise, with at least 745 poached last year and over two a day being shot by poachers so far this year, the International Union for the conservation of Nature (IUCN) reported on Tuesday.

The Swiss-based inter-governmental body said the poaching rate — driven by the Asian demand for the animal's horn for use in Chinese traditional medicines - could threaten the rhino's long-term survival.

"Well-organized and well-funded crime syndicates are feeding the growing black market for rhino horn," said a statement from Mike Knight who chairs a team of experts within IUCN Special Survival Commission.

"High levels of consumption, and especially the escalating demand in Vietnam, threaten to soon reverse the considerable conservation gains achieved over the last two decades," Knight declared.

IUCN says the two principal rhino species, the Black and the White, total some 26,000 in Africa, just 5,055 Black rhinos and 20,405 White.

Poaching of the animals between 2011 and 2012 rose by 43 percent for a total of 745 animals, bringing a decline of 3 percent in the total population, the organization reported.

The statement said the crime syndicates involved in the lucrative but illegal trade used Mozambique, from where many poachers crossed into South Africa, as a major transit point to ship the horn, mainly to China and Vietnam.

South Africa's Kruger National Park near the Mozambique border is home to the world's largest rhino population. A total of 668 rhinos were illegally killed in South Africa last year, according to the IUCN.