The Hawks have seized an illegal shipment of abalone worth an estimated R6m at the Grobler's Bridge port of entry in Limpopo, a statement said on Friday.
The seizure was the result of a "joint operation" between the Hawks' serious organised crime investigation unit and Grobler's Bridge border police, Captain Matimba Maluleke said.
They had received an anonymous tip about a truck that was "allegedly smuggling abalone from South Africa to Botswana".
The abalone shipment was discovered after authorities stopped a truck whose two occupants allegedly jumped off the vehicle and ran away when authorities approached.
About 10kg of dried abalone, worth over R6m, was found hidden inside potato sacks.
The authorities also found two passports belonging to foreign nationals.
The Hawks were currently investigating.
Last month, an abalone syndicate poacher was sentenced to 20 years in jail by the High Court in Port Elizabeth.
Judge Dayalin Chetty sentenced 48-year-old abalone syndicate poacher Morne Blignaut for two counts of racketeering and one count of operating a fishing establishment without a permit.
Also in September, in a damning report published by international wildlife trade monitoring network Traffic, South Africa was said to have lost at least 96 million units of local abalone in the past 17 years.
The rate at which abalone were being poached left the future of the snail-like sea creature in danger of becoming extinct, the report said.
Traffic believed the only way to protect the species from going extinct, and not lose the income legally fished abalone generates, was through international collaboration to regulate its trade.