The head of South Africa's Department of Justice could "intervene" to prevent Oscar Pistorius' early release from prison.

The department said in a statement sent to The Associated Press on Wednesday that Justice Minister Michael Masutha is checking to see if the decision by a parole board to approve Pistorius for house arrest was correct.

The justice department says Masutha is "seeking legal opinion (on) whether he is empowered by law to intervene if necessary." It said the minister would announce a decision before Friday, the day Pistorius was expected to leave jail.

The double-amputee runner has served 10 months of a five-year sentence for manslaughter for killing girlfriend Reeva Steenkamp in 2013. He was approved by a parole board to serve the remainder under house arrest.