The 32-year-old was granted parole after serving 11 years of a 20-year sentence for fatally stabbing Bulgarian law student Andrei Monov, 23, during a brawl in the capital Sofia in 2007.

He has consistently maintained he acted in self-defence that night after intervening to prevent Mr Monov and a group of friends from attacking two Roma, or gypsy, men.

Multiple Facebook support groups, including Free Jock and Anarchists Worldwide, posted photographs of Palfreeman being led out of Sofia Central Prison by plainclothes police and prison officers on Friday.

The Australian wasn't allowed to speak with assembled reporters but yelled out: "Thanks to Desislav Traykov, Deputy Chief of the Prison!" before he was bundled into a car and taken to the Busmantsi Immigration Detention Centre.

Mr Traykov resigned from his position two weeks ago after becoming embroiled in a scandal involving a prisoner convicted of drug smuggling.

Palfreeman will reportedly remain at the detention centre until he receives a new Australian passport but it is still unclear whether he will be extradited and when.

The Sydneysider told his appeal hearing on Thursday that he will continue his work for prison reform in the Eastern European country no matter where he ends up.

"If I go out on parole I want to continue my activity as a part of the Bulgarian Prisoners' Rehabilitation Association," he told the court, according to court documents released on Friday.

"If I am not released, I will also continue with the reforms of the Bulgarian prison system, so the difference is which side of the fence I will be."

The court's ruling found that Palfreeman never posed a risk to anyone in prison and specifically mentioned his work with the BPRA as a factor in his successful application.

"Only very positive information is highlighted in relation to the convicted person, with good communication skills, leadership attitude, tolerance towards others, inquisitive, with expressed interests in various fields, active, initiative, consistent and persistent in realisation of its goals, sensitive and reactive to the social environment, well-meaning and responsive in general, without racial or discriminatory attitudes," the judges panel said.

"His activity in the Bulgarian Prison Association for Rehabilitation, registered by him, is noted. He is noted to be emotionally and socially mature."

Palfreeman's father Simon said his son wants to continue helping the prisoners in Bulgaria.

"It's become a passion of his to be able to do that," Dr Palfreeman told ABC Radio.

"But I think realistically he understands that he won't be able to stay in Bulgaria to achieve that."

Australian Associated Press