Australian Jock Palfreeman could well be returned to prison in Sofia despite being granted parole earlier this year, a Bulgarian judge has warned.

Bulgaria's highest court on October 7 heard an extraordinary appeal to have Palfreeman returned to jail and his case reopened.

A decision was meant to be reached within two months but with the time limit elapsing on Monday, there's no word yet from the Supreme Court of Cassation.

That could spell bad news for the 33-year-old Sydney man, according to Sofia City Court judge Emil Dechev.

Judge Dechev was one of more than 300 Bulgarian judges who signed a petition defending the appellate court's decision to grant Palfreeman parole in September.

He says the panel of three judges who granted parole has since been threatened with disciplinary action.

"The fear that Jock will be returned to prison is real," Judge Dechev told AAP.

Judge Dechev said the appeal - launched by Bulgaria's powerful prosecutor-general - is considered by local lawyers to be inadmissible under the criminal procedure code.

He said this meant the Supreme Court of Cassation could have discontinued the proceeding at the end of the October hearing.

"When a case is discontinued the decision is usually not very long in pages and it doesn't represent any factual or legal difficulties," Judge Dechev said.

"But it is a different story when the court accepts that the request is admissible and has to pronounce on its grounds and merits.

"If the Supreme Court of Cassation will pronounce on the merits of the request, then the probability to renew the case for granting parole is real, and he could be sent back to prison."

Judge Dechev said the threat of disciplinary action against the independent judges was an attempt "to silence or intimidate" them.

Palfreeman served 11 years behind bars in Sofia after being found guilty of murder and attempted murder for stabbing two Bulgarian youths during a street melee in late 2007.

He's always maintained he acted in self-defence.

Meanwhile, the 33-year-old's grandfather, Tony Palfreeman, has had to abandon a "light on the hill" he installed for Jock at his Wollombi farm due to the state's unprecedented bushfires.

He evacuated his property in the Lower Hunter on Wednesday night after an out-of-control blaze approached from the west.

"I felt very sad to leave the light that has been shining for Jock for 12 years throughout his ordeal in a Bulgarian prison," the 88-year-old told AAP.

"It's hard to accept that when he does finally come home, the light could be gone, extinguished by these terrible fires as they overrun the hills and paddocks."

Tony Palfreeman said volunteer firefighters had done an "enormous and very difficult job" trying to contain the fires but they desperately needed more support.