Customs officials said Thursday they had seized $3.5 million (about R52 million) worth of rhino horns disguised as printing accessories at OR Tambo International Airport.
Eighteen pieces of horn were discovered during a routine inspection at a courier facility at the airport, a statement said.
They were passed off as printer cartridges and were destined for Malaysia.
An x-ray scan revealed "objects resembling the shape of rhino horns", it said.
No arrests were made as the package was sent through courier.
It is the fourth seizure made at the airport since July 2020 with rhino horns worth around $15.6 million prevented from being smuggled.
South Africa, home to about 80 percent of the world's rhino population, has been a haven for poachers. But the number of rhinos slaughtered have been dropping over the past six years.
In 2020, the number of rhinos killed plunged by 33% to 394 over the previous year, the environment ministry said on Monday.
Poaching is fuelled by a market for rhino horns in Asia, where they are used in traditional medicine or as a claimed aphrodisiac.