The suspicious shipment - destined for Malaysia - was noticed during searches conducted by the customs unit.
In 2020, the Kruger National Park recorded 1,573 poaching incidents, a decrease of nearly 22% compared to 2019.
The rhino’s carcass was found by a farmworker who was patrolling the area on Friday.
Two are security guards, while the other works with the technical services division at a rest camp.
The two security guards and another worker from the technical services division were arrested earlier this week on Tuesday during an operation between Sanparks and police.
A report published and compiled after interviews with 73 convicted wildlife offenders in SA's jails concluded that 70% of them were forced into crime to make a living.
Conservationists are concerned that with the economic downturn caused by the coronavirus and the decline of tourism, many people are desperate, and some may turn to poaching.
And the number of incidences has begun to edge higher again as coronavirus lockdown measures are eased, she added in a statement.
The horns, which were discovered during a routine inspection at the airport, were disguised as art and are valued at about R115.66 million.
Customs officials at OR Tambo International Airport have discovered 41 pieces of rhino horn valued at R115.66 million in a consignment declared as 'fine art'.
The exercise in Pilanesburg National Park and the Mafikeng and Botsalano game reserves — all northwest of Johannesburg — leaves the rhinos with horn rumps too small for poachers to bother with, Nico Jacobs said.
The Wildlife Justice Commission (WJC) warned that criminal gangs were adapting to tighter border controls amid the COVID-19 pandemic.
Poaching is fuelled by the demand for rhino horn in Asia, where it is coveted as traditional medicine or an aphrodisiac, and can fetch up to $60,000 per kilogramme.
Earlier this week, poachers shot and killed a young rhino and made off with its two tiny horns. Another rhino was shot and wounded and later died.
The country is home to just under 400 rhinos, according to Rhino Conservation Botswana, most of them roam the grassy plains of the northern Okavango Delta.
For the past few years, Mark Boucher has used his star power to attract big personalities and companies to support the cause that he sees as everyone’s cause.
Carlos Sithole opened fire on rangers in the park in 2015. Rangers returned fire and arrested him.
The seven were arrested nine months ago after police found more than 20 kilogrammes of rhino horn pieces stashed in a house they rented in Victoria Falls. They denied the charges.
