The parents of an Australian man detained in Bulgaria are calling on Prime Minister Scott Morrison to intervene and help secure his release.

Palfreeman has maintained he acted in self-defence since he was imprisoned more than a decade ago.

Sotir Tsatsarov has applied to country’s highest court to revoke parole granted to the Australian last week

The Australian being held in a Sofia immigration detention facility says the Bulgarian authorities keeping him locked up after he won a parole appeal last week are using his case to further their own political agenda.

Bulgaria's powerful prosecutor-general seeks to have Australian Jock Palfreeman returned to jail, amid a political firestorm over a decision to free him on parole halfway through a 20-year-sentence.

In a new twist to the saga of Sydneysider Jock Palfreeman, 292 Bulgarian judges sign a letter defending the appellate court's decision to grant the Australian parole.