The fifth was killed by an elephant and later "devoured" by a pride of lions, park officials said in a statement.
"Entering Kruger National Park illegally and on foot is not wise, it holds many dangers and this incident is evidence of that," said Glenn Phillips, managing executive of Kruger National Park.
The four alleged poachers who survived were arrested and will appear in court "in due course," the statement said. They will remain in custody until Friday, pending bail, reported Times Live, a South African news site. Authorities have launched an investigation into the alleged poacher's death and accomplices.