Former Oprah Winfrey girls' academy matron denies assault charges in South Africa

Virginia Mokgobo, 27, arrested in November and out on bail, is facing charges relating to common assault, harassment and soliciting a minor to perform indecent acts and verbal abuse.

She appeared in Sebokeng magistrate court, south of Johannesburg.

Charges: Virginia Mokgobo appears at Sebokeng magistrate court on 13 charges of assault, sexual assault and criminal injury

'She pleaded not guilty to all the charges, they are reserving her defence, I don't know till when,' said state prosecutor Etienne Venter.

Devastated: Billionaire Oprah Winfrey is said to be very upset at the charges at her $40 million academy

Testimony from six minors will be heard by video and media will be allowed in court on Friday.

'The reason is that the children are scared to be seen,' Venter said.

Winfrey, a billionaire philanthropist who has herself told of suffering sexual abuse as a child, has described the charges against the matron as one of the most devastating experiences of her life.

The $40 million Oprah Winfrey Leadership Academy for Girls opened in January 2007.

In March last year, some parents complained the school was too strict and its restrictions on visits, phone calls and email contact were comparable to rules in prisons.

Then in May, they complained their children were not allowed junk food and, when they visited the school, they had to go through a security gate.