In an open letter to the world's largest rhino breeder, Mpumalanga-based John Hume, published on his own JV and the Big Cats website, Varty said Hume should ask the environment minister for permission for a one-off auction of all privately owned horns.
"Point out that the precedent was set in the 1980s when South Africa's National Parks had ivory auctions in which Japanese, Taiwanese and Chinese buyers participated in the purchase of ivory from culled elephants in Kruger National Park," he said. "The money from those auctions went back into the protection and conservation of elephants in South Africa."
If the minister did not grant permission for the auction, he wrote, Hume should "create a global event", similar to the way Kenyan conservationist Richard Leakey focused attention on elephant poaching when he persuaded then-president Daniel arap Moi to burn 12 tonnes of ivory in 1989.
"In your case, you go ahead with the auction, informing the South African government of your intentions. If you would like me to stand beside you, I will do so," Varty said.
"You invite 100 private individuals who have rhino horn from dead or dehorned rhino to join you in the auction.
"If you were on your own, the government could arrest you. I doubt if the government could arrest 100 high-profile private individuals trading openly in rhino horn and advertising the auction globally."
The missive generated heated response on social media networks, rekindling debate on whether opening the trade in horn will stop rhino poaching. With this year's death toll climbing past 410 rhinos, concerned groups are awaiting a decision on the trade debate promised by the environment department's "rhino conservation issue manager", Mavuso Msimang, by the end of September.
Varty was criticised by anti-trade groups for supporting the argument of many private rhino owners at workshops convened by Msimang in recent months in the run-up to a seminal meeting of the Convention on International Trade in Endangered Species (Cites) early next year. Private ranchers, who own about 25% of the estimated 18000 white rhinos left in South Africa and a large part of the almost 20 tonnes of stockpiled horn, argued that the only way to halt the slaughter was to lift the trade ban imposed in 2009.
Varty courted controversy when he defied conservation dogma in the 1990s by setting up a tiger-breeding project in the Free State because he believed the Indian government was not doing enough to save the big cats from extinction.
He said present interventions to save rhinos were not working. "We have lost 10 rhinos on our family game reserve in Sabi Sand and now have to hire a small army to protect the rest. It's a war."
Hume, who owns hundreds of rhinos and dehorns them regularly, said Varty's open letter supported his view that the only way to stop the poachers was to sell horns to Asian countries, where they are prized as medicinal remedies.
"My answer is that I wish I had the guts to take on the whole world, but at the age of 70 I don't want to buck the system. I toe the line, work with Cites and stick within the law, even if it's bad for rhinos," he said.
Hume's lawyer, Izak du Toit, said although Varty's suggestion was "bold and noble", he was not convinced it could work legally. "But the public lobbying value may be worth it to get the world's attention. Desperate situations call for desperate measures."
Environment department spokesperson Albi Modise stressed the "need to continue working with all stakeholders and our entire South African society if the war on rhino poaching is to be won".