Shayden Thorne, 25, was one of 11 people detained by Saudi authorities on November 25, 2011, on terrorism-related offences.

Yesterday sources said the main allegation against Mr Thorne was that he was preparing to travel to Afghanistan to fight.

His brother, Junaid, 23 was detained for two months for protesting against Shayden's arrest in December 2011.

According to their mother, who has asked to remain anonymous, Junaid is in hiding in Riyadh.

Speaking from Perth, the boys' mother said Shayden had been making a living in Saudi Arabia by travelling from mosque to mosque leading prayers.

She said Shayden and Junaid, the eldest of her eight children, were "normal young men" who were interested in cars and liked to keep fit.

They were born Muslim, she said.

The boys' father - a West Australian Aboriginal man from the Noongar people of the southwest - was a Muslim when she met him.

The couple separated, and she married a Moroccan man who received a job offer in Saudi Arabia in 1996. She went there with him and the two boys, returning to Australia with them just once in 2000 for about a week.

The woman said she was shocked when Shayden's lawyer detailed his allegations that he had been tortured while in jail. The allegations were laid out in an affidavit he had presented to the court, she said.

She said he was hit with cables, and kicked and punched. His wrists and ankles were tied together and he was hit in the genitals until he passed out.

She said during jail visits her son had swollen fingers he said were the result of playing volleyball.

She now believed he was covering up the fact he had been tortured so that he would not worry her.

"I heard about torture in Guantanamo Bay when it was the Americans doing it to other people but to find out that it's the Saudis are doing it really shocked me," she said.

"I respected the Saudi government but that's no different."

However, The Australian understands Shayden has never complained to Australian officials about mistreatment at the hands of the Saudis, despite receiving six visits from Australian consular officials in prison.

Mr Thorne has made other complaints -- that he lacks access to sunlight, exercise facilities, a varied diet and that he remains in a smoking cell.

Yesterday Foreign Minister Bob Carr said the Australian government was not in a position to determine "who's right or who's wrong".

"We can't run a trial," he said. "We can't mount their defence for them. We can make representations, however, about the time it's taking."

Shayden's Facebook page lists Osama bin Laden as an inspirational person and carries the words, "Osama bin Laden, God have mercy on him". The page was last updated on November 24, 2011, a day before his arrest.

Shayden's mother said his lawyer had told her that a laptop with allegedly terrorist material on it was central to the case against him, but that it did not belong to her son.

She said she knew he had borrowed it from a mosque.

She said Shayden was also accused of holding funds to pay for terrorism but he had the equivalent of $300 that was to be paid to a car rental company after he damaged one of its vehicles in an accident.

Senator Carr said the Australian government had made more than 50 representations on behalf of Shayden Thorne.