Reinach Tiedt and Gert van Schalkwyk's recent application for leave to appeal against an earlier ruling that they return to the facility, was dismissed on September 16 by the high court in Pretoria.
The pair reported to Zonderwater Prison, north of Pretoria, on Monday for re-admission.
The two had been under house arrest for almost two years.
Their lawyer, Jenny Brewis, said they felt an urgent petition to keep them out of prison would jeopardise their chances of parole.
"We've decided it wasn't conducive," Brewis said. "The thing is, I don't want my clients to jeopardise their chances of being eligible for parole, which would be in early February next year ."
"It was decided to respect the court's decision and respect due process. They will let things take its course."
Tiedt and Van Schalkwyk were readmitted to the Zonderwater Prison, north of Pretoria, earlier in the day.
Last week, the high court in Pretoria dismissed their recent leave to appeal against an earlier ruling that they return to the facility.
"The two reported for re-admission today [Monday] at 12.30pm. They have now been re-admitted," said correctional services regional commissioner Zacharia Modise.
Brewis said her clients were distraught at the decision, but were positive their return to prison would work in their favour.
The two, with Christoff Becker and Frikkie du Preez, were sentenced in January 2005 to 12 years in prison for murdering a homeless man in a Pretoria park in 2001.
They started serving their sentences in August 2008 after an unsuccessful appeal.
A Pretoria magistrate converted Tiedt and Van Schalkwyk's sentences to correctional supervision in December 2011, after an application by the Parole Board.
Correctional Services appealed against the decision and the high court ruled in June that the magistrate's ruling had been based on an error in law, and that the two must return to jail.
Judges Hans Fabricius, Ephraim Makgoba and Wendy Hughes found that the pair were not entitled to parole if more than five years of their sentence remained. – Sapa