Subsequent farmers also hunted the elephants till there were only 16 left in the Addo region.
ERP said by transporting elephants to the Eastern Cape, it aimed to establish viable breeding populations and eliminate the need for culling in overpopulated reserves.
"These two introductions are the result of months of painstaking logistical preparation by ERP staff, covering activities including site visits, permit applications, and detailed planning to manage capture, transport, release and associated logistics," it said.
The translocation included 23 hours of non-stop driving in customised trucks.
The family groups were relocated to two private reserves. Mount Camdeboo welcomed six individuals, while Buffalo Kloof added 10 to its existing herd.