Johannesburg - Around 40 rhino horns worth an estimated R160m have been stolen from the safe of a tourism organisation in Mpumalanga, a paper reported on Monday.
The horns were taken from the Mpumalanga Tourism and Parks Agency (MTPA) at the weekend, the Lowvelder newspaper reported.
"The culprit, or culprits, cut open two steel safes fitted with double locks," a source from the agency said.
Dex Kotze, conservationist and CEO of South African jeweller Jenna Clifford, which backs a campaign against rhino poaching, said the haul could be worth as much as R160m.
Neither the MTPA nor the police could be reached for comment.
Poaching of rhino is on the rise, with more than 270 killed already this year, nearly half in the Kruger National Park.
The horns are much sought after in parts of Asia, particularly in Vietnam, for use in traditional medicine, even though they are made of keratin, the same as human fingernails.
Poachers often kill the rhino with semi-automatic rifles, hacking off the horns and leaving the animals wounded or dead.
South Africa is home to nearly 20 000 rhino, which make up 70 to 80% of the world's total rhino population.
Illegal hunting of rhino in parks continues despite air and foot patrols, as well as increased numbers of rangers assisted by soldiers.