An Australian man imprisoned in Bulgaria has ended his hunger strike against unfair treatment after 33 days without food.

Jock Palfreeman is 11 years into a 20-year sentence for fatally stabbing Bulgarian law student Andrei Monov, 23, during a brawl in the capital Sofia in 2007.

AAP

The Sydney man stopped eating on April 21 to protest the unfair treatment he says he has suffered for his role in the Bulgarian Prisoners' Rehabilitation Association, the country's first prisoner advocacy union.

The BPRA announced Palfreeman ended his fast on Thursday, as he had been given permission to receive a visit from his family and to give media interviews.

"Jock Palfreeman has ended his hunger strike today on its 33rd day," the union said in a statement on Facebook.

"The reasons for this are personal. On one hand, this weekend he will be visited by his family, travelling all the way from Australia. On the other - he wants to be able to speak with the media who have contacted the prison requesting interviews."

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It's understood Palfreeman's father Simon will be allowed to visit him for the first time in months.

Palfreeman's lawyer Kalin Angelov said the hunger strike had been in response to Bulgarian authorities cracking down on the Australian for exposing corruption in the country's prison system and the abuse of inmates.

Mr Angelov said Palfreeman had been a model inmate with a completely clean record, until a new national government was elected in May 2017. The incoming administration then began to systematically wind back his privileges, his lawyer said.

Mr Angelov said his client had been sacked from his prison job, banned from receiving visitors and denied access to phone cards to contact the outside world.

At one point, his lawyer claimed, Palfreeman was also moved from a low-security facility to the Sofia Prison hospital's infectious disease unit, where he was kept with tuberculosis patients in an attempt at "deliberate infection".