Mr Greste returned to Australia from Cairo on Saturday where he had been lending support to his brother, jailed Australian journalist Peter Greste.

He described the month-long journey, where he was allowed to visit Greste six times, as “definitely worthwhile”.

“I’m so glad I did it,” Mr Greste said.

“It really helped Peter a lot having family over there.

“He said it was invaluable for me to be able to be there with him in court.”

Greste is facing up to seven years in jail, accused of backing the black-listed Muslim Brotherhood and portraying Egypt as being in a state of “civil war”.

Mr Greste said it was hard to see his brother, who is only permitted one hour of exercise a day, in Cairo’s notorious Tora Prison.

“Obviously it was pretty confronting visiting him in a place like that,” he said. “The prison conditions are extremely tough.

“He’s in a cell 3m by 4.5m with three others in that cell ... up until yesterday he has been denied reading material.”

The father-of-three said he regretted not being able to bring his brother home, but acknowledged a recent letter from Egypt’s interim president Adly Mansour to his parents stating he “will spare no effort” to quickly resolve Greste’s case, was promising.

Mr Greste’s younger brother, Michael, has now taken up the post in Cairo.

The Greste family believes there is little or no evidence to substantiate the charges against the journalist, who is due to reappear in an Egyptian court on March 24.