A Sydney man who was pulled off a bus and murdered by Taliban fighter was killed just for being Australian, local authorities say.

Sayed Habib Musawi was traveling on a bus from Kabul to visit relatives in Ghazni province on September 20 when he was killed, the ABC reports.

Ghazni's deputy governor Mohammad Ali Ahmadi told the ABC Radio's AM program the 56-year-old Afghan migrant was targeted because he was an Australian citizen.

"Of course the reason is that he was an Afghan-Australian," he said.

Australian Sayed Habib Musawi was reportedly tortured and killed by the Taliban in Afghanistan. (The Guardian)

"He didn't do anything besides that – he didn't do anything wrong, he wasn't a criminal, he wasn't involved in government activities.

"The reason of his murder was very clear – that he was a dual citizen, he came from a country that Taliban think is an infidel country."

Mr Ahmadi said that when Mr Musawi's body was found on the side of the road his hands were tied behind his back and there were signs he had been beaten.

"The murderers beat and tortured him. People in the area contacted us, so we ordered the district security chief to investigate," Mr Ahmadi said.

"After an investigation it became clear that the dead body belongs to Sayed Habib, an Afghan Australian who came to visit his family."

Mr Musawi's son 23-year-old son Nemat, said he had spoken to his father only a few days before he was killed

"The whole family is devastated. We can't believe it. I just spoke to my dad a week-and-a-half ago and he was with family members and he said he was going to call me back," he said.

"I was waiting for his call and then the next thing I hear he's been shot dead by Taliban three times.

"It seems like it was all set up, because they just stopped the bus on the way to Ghazni and then they just went straight to my dad ... called him and pulled him out of the bus."

The Department of Foreign Affairs and Trade said it was still trying to confirm reports of Mr Musawi's death.