South Africa's ex-Olympic runner Oscar Pistorius will be released from prison in January after he was granted parole on Friday, a decade after he shot dead his girlfriend, Reeva Steenkamp, in a crime that gripped the world, prison authorities said.

A parole board reviewing whether Pistorius, 37, was fit for social re-integration had decided to allow him out of prison early, the department of correctional services said.

"Mr Pistorius will complete the remainder of the sentence in the system of community corrections and will be subjected to supervision in compliance with parole conditions until his sentence expires," the department said.

He will be released on January 5.

A spokesman for Steenkamp's family said that as part of the parole conditions, the ex-athlete will have to do community service and attend therapy for anger and gender-based violence issues.

He will also not be allowed to leave the Pretoria district of Waterkloof without prior authorisation, Steenkamp family spokesman Rob Matthews said.

Before being let out, Pistorius will undergo a pre-release programme that is to prepare him for life outside prison, said department of correctional services spokesman Singabakho Nxumalo.

"Not everyone will find it easy to adjust," Nxumalo said, adding the scheme was to prepare inmates that "not everyone will welcome you as others will open their arms".

Earlier Steenkamp's mother told the parole hearing that she did not believe the ex-athlete was rehabilitated for he had not shown true remorse.

"Rehabilitation requires someone to engage honestly, with the full truth of his crime and the consequences thereof. Nobody can claim to have remorse if they're not able to engage fully with the truth," June Steenkamp said in a statement to the board.

But her spokesman told the board she was not opposing parole for Pistorius.

The hearing held at a correctional centre outside Pretoria where he is currently detained, was Pistorius's second shot at parole in less than eight months.

He lost a first bid in March when the board found Pistorius had not completed the minimum detention period required to be let out.

The Constitutional Court last month ruled that was a mistake, paving the way for a new hearing.

Pistorius killed Steenkamp, a model, in the early hours of Valentine's Day 2013, firing four times through the bathroom door of his ultra-secure Pretoria house.

Known worldwide as the "Blade Runner" for his carbon-fibre prosthetics, he was found guilty of murder and given a 13-year jail sentence in 2017 after a lengthy trial and several appeals.

He had pleaded not guilty and denied killing Steenkamp in a rage, saying he mistook her for a burglar. (AFP)