"She has not been found guilty of anything yet. She is suspected of doing it. She has been put on precautionary suspension," spokesperson Ramona Baijnath said.
The woman would face a disciplinary hearing.
More details would be provided shortly, said Baijnath, who declined to name the official.
In a statement, Corruption Watch identified the official as Debbie Joubert. It said she had allegedly been erecting shacks at the Roodeplaat Dam Nature Reserve, north of Pretoria, and renting them out to her employees.
It was also alleged that she competed directly with the department by channelling visitors to a private resort called Angling Grounds, which was run by her husband.
Corruption Watch said her position at the department included the task of managing the reserve.