Bulgaria's justice ministry has proposed that the heaviest sentence in the country's Penal Code – life imprisonment without parole - is abolished.

A part of the proposed amendments were published online on the site of the department Wednesday.

Should the proposal be adopted, it means that the convicts, found guilty of the heaviest crimes, will have the chance to walk out of prison after serving twenty years and behave well.

The news comes a day after Bulgarian prosecutors demanded a life sentence without parole for the Australian citizen Jock Palfreeman on the final hearing of the appeal trial.

Palfreeman was convicted in December 2009 of fatally stabbing one man and wounding another during a street brawl in the Bulgarian capital, Sofia, in 2007. He was sentenced to twenty years in jail.

Palfreeman, now 24, from Sydney, pleaded not guilty, claiming he acted in self-defence after intervening to prevent an attack on a group of Roma, or gypsies.

He has been in custody since the December 2007 incident.

Bulgarian prosecutors, who asked for life imprisonment, claim Palfreeman was not provoked and did not act in self defence.