Three more rhino carcasses were found in the Kruger National Park on Thursday, following the discovery of eight earlier this week, said SA National Parks (SANParks).
Two suspected poachers were arrested, said spokesman Reynold Thakhuli.
He said earlier that game rangers killed two suspected Mozambican poachers in a shoot-out during an anti-poaching operation in the park on Wednesday night.
They seized a rifle and other hunting equipment.
The operation was conducted after the discovery of the dehorned carcasses of eight rhinos on Tuesday.
The additional rhino carcasses were found after an aerial search on Thursday morning.
SANParks has asked people to provide it and the police with information which could lead to the arrests of poachers.
Last year, about 443 rhinos were killed for their horns in South Africa, with 333 killed in 2010. (Sapa)
