Oscar Pistorius' release from prison has been put on hold by South Africa's Department of Justice, which said his case must be reviewed again by a parole board because he was approved to be moved to house arrest too early.

Pistorius was due to be released on Friday after serving 10 months of a five-year sentence for manslaughter for killing girlfriend Reeva Steenkamp.

Justice department spokesman Mthunzi Mhaga told South African broadcaster eNCA it was uncertain if the parole board would be able to meet to consider Pistorius' case again before Friday.

Pistorius should have served one-sixth of his jail sentence - 10 months - before being considered for release, Mthunzi said. However, he was considered and approved for release to correctional supervision in June, only eight months into his sentence.

"It is apparent therefore that the decision to release him on 21 August 2015 was made prematurely on 5 June 2015 when the offender was not eligible to be considered at all," the justice department said in a statement.

Spokesman Mhaga said "the decision of the parole board will have to be suspended".

Justice minister Michael Masutha had earlier warned he was taking legal advice on if he had the authority to "intervene" and prevent Pistorius' early release.

Source: AP