A man accused of rhino poaching has claimed he was raped by national park rangers who detained him and then assaulted him with the end of a rifle.

Santos Ngoveni, 31, was arrested in Skukuza on charges of unlawful possession of a firearm and ammunition. However, he told police his confession to Kruger National Park rangers was made under duress and that he had been raped with the barrel of a rifle.

"During his arrest, KNP rangers forced Ngoveni to admit possession of a gun. Ngoveni told the rangers that he doesn't have a gun, his friends ran away with the firearms but the rangers insisted that he admit to possessing a firearm," his lawyer Mike Nonyane said.

The attorney is now asking Skukuza Magistrate's Court where Ngoveni is so he can enter a plea on 9 September to charge the rangers with rape. They already stand accused of grievous bodily harm.

Ngoveni is being detained at the Skukuza police station and has received medical treatment.

"The rangers brutally assaulted Ngoveni ... this case was supposed to be a rape case. In terms of Sexual Offences Act, the conduct of the rangers constitutes rape," Nonyane was quoted as saying in the South African Times.

Ngoveni has said he is grateful to be alive. "I just thank God for my life, I am recovering and the injuries are healing," he said.

Kruger National Park has said in a statement that its management was not aware of the incident and awaits the decision of the courts.