A Sydney man imprisoned in Bulgaria has been refused to be transferred to an Australian prison. 26-year-old Paul "Jock" Palfreeman is serving his 20-year sentence after the European country found him guilty of murder with hooliganism and attempted murder in 2009.

Palfreeman, 26, was sentenced in December 2009 for stabbing a 20-year-old man to death and wounding another man in Sofia two years prior. He served almost six years of his sentence in the Sofia Central Prison, and was hoping to transfer to his home country.

Australia had sent a request to Bulgaria for its citizen to be transferred home and serve the remaining of his sentence in the country.

However, Bulgaria's prosecutor's office denied his request on Tuesday, claiming that he has repeatedly "committed gross violations" of prison regulations.

"Taking into account the limited time that has been served as part of the 20-year sentence and the above mentioned conduct of the convicted person, Chief Prosecutor Sotir Tsatsarov has refused the transfer," the prosecutor's office said.

Both countries are both signatories to a prison transfer agreement, which would have allowed Palfreeman to be transferred from the notorious Sofia prison to a prison in Australia.

The convict's father, Dr Simon Palfreeman, was surprised and baffled at the rejection.

"Only six weeks ago the Australian Government assured Jock's family that the Bulgarian authorities had received the application for transfer with a very positive attitude," he has been quoted by ABC News as saying.

"Their main concern was that the outstanding fines and compensation had to be paid. In fact the prison director had a senior DFAT representative that Jock's behaviour in prison was much improved and that he would be writing a positive report to the prosecutor general."

Dr Palfreeman added, "I also find it baffling why the Bulgarian authorities, having promised the Australian Government a reply to their request delivered in person by our ambassador, would do so through a press release."

For Bulgaria Helsinki Committee, the country's leading human rights group, the decision not to transfer the Australian prisoner might have something to do with pressure from the dead victim's father, who is now a government MP.

"If the chief prosecutor submitted to pressure from the family, from a member of the parliament, that is very disturbing," BHC president Krassimir Kanev said. "There is certainly an undue influence."

Palfreeman claimed in court that he got into a bar brawl that ultimately led to a person's death because he was trying to save two gypsies from being beaten by a gang of local youths. However, the court said his self-defence claim wasn't admissible because he was armed with a knife before he went out to drink.