Two of the rhino died in the attack on Saturday and their corpses were found within sight of the reserve’s main gate, The Witness newspaper reported on Monday.
Head ranger Divan Vermaak said the third rhino was recovering.
According to the report the rhino were closely watched at night. The three rhino had been darted before they were dehorned.
“For the past week we have not let them out of our sight at night, especially with it being full moon.
Maybe that is why the poachers took such a risk by attacking in broad daylight,” Vermaak was quoted as saying.
Vehicles entering the reserve, located near Pietermaritzburg, were being searched.