The company owned by the family of Oscar Pistorius is facing a legal battle over allegations they fixed agricultural prices for more than 13 years.

Hendrik Pistorius & CO, a company founded by the grandfather of the convicted Paralympian, has been charged for allegedly fixing prices in the agricultural industry since 1995.

The company, responsible for a huge percentage of the Pistorius family's wealth, also spread into areas such as property, mining and tourism.

The competition commission alleges Hendrik Pistorius & CO entered into price fixing agreements with suppliers and sellers of the product aglime, using the Fertiliser Association of Southern Africa as a platform for the price-fixing.

Legal representatives of the company, currently owned by Oscar's uncle, Leo, deny the allegations.

"The complaint relates to allegations by a disgruntled customer and previous business partner dating back to 2008 and all (and every) allegations of price-fixing is absolutely denied," a spokesperson told the Sunday Independent.

If found guilty, Hendrik Pistorius & Co could be fined 10% of its total turnover since the time of the alleged price fixing.

Pistorius is currently serving a five year jail term for the manslaughter of his girlfriend Reeva Steenpkamp. From August 2015 he could serve his term under house arrest.