Security forces confronted a gang of five at the well-known tourist destination. Another member of the group was wounded.
Rangers say they recovered a firearm, ammunition and other tools used for rhino poaching from the scene.
It is the latest in a series of attempts to reverse the rising trade.
Demand for rhino horn has soared in recent years - fuelled by the belief in parts of Asia that it has medicinal properties.
The black market price of rhino horn is now in the region of Â£35,000 ($55,000) a kilogram.
Last year, South Africa recorded more than 300 cases of poaching.
Despite the prospect of high-level prosecutions, the financial rewards for criminals  are helping to fuel the trade.
Three suspected rhino poachers have been shot and killed by rangers in South Africa's Kruger National Park.