A prison review board has up to four months to decide whether Oscar Pistorius will be released into house arrest, a spokesman for South Africa's justice ministry said.
Mthunzi Mhaga also said the department has not yet had a response from Pistorius's lawyers to justice minister Michael Masutha's decision to halt the release.
Mr Masutha put Pistorius's early release - scheduled for Friday - on hold, saying it was approved too soon.
The justice ministry said it was approved eight months into his five-year prison sentence, when the athlete should have served 10 months before being considered for release.
Pistorius was convicted last year of manslaughter for killing his girlfriend Reeva Steenkamp in 2013.
Pistorius family spokeswoman Anneliese Burgess said no decisions have been made yet by the family.
"The family will take their time to calmly consider the way forward," she said.
News of the postponed release came to the Steenkamp family as they held a beachside commemoration for Reeva Steenkamp on Wednesday, what would have been her 32nd birthday, said Jacqui Mofokeng, a member of the women's group who petitioned the justice minister to delay Pistorius's release.
"The mood changed," said Ms Mofokeng, who was also part of a group of women who accompanied the Steenkamps during the trial.
"They sent a number of messages to individuals to say, 'Thank you very much. This is a better birthday than last year'."