Egyptian prosecutors appear to be having a tough time mounting a case against detained Australian journalist Peter Greste, his father says.

The father of detained Australian journalist Peter Greste says it’s obvious Egyptian authorities are struggling to make a case against his son after he was refused bail in a Cairo court.

Juris and Lois Greste had hoped their son would be released from jail after Prime Minister Tony Abbott last week called interim Egyptian president Adly Mansour about the case.

But the Al Jazeera journalist was refused bail when he and some of his colleagues again faced court on Monday, and he will now spend another 10 days in jail before the case returns to court.

Greste told the court that claims he was linked to the Muslim Brotherhood, the black-listed movement of deposed Islamist president Mohamed Morsi, were preposterous.

“I would like to emphasise that we pose no risk to either the state of Egypt or any individual,” he said.

Speaking to reporters in Brisbane, Juris Greste said it appeared Egyptian prosecutors were finding it tough to mount a case against his son.

“To even the casual observer it must look pretty obvious that there’s a struggle to make the case,” he said.

“I don’t think anybody could say that they’ve produced any kind of tangible evidence yet, not even yesterday.

“That’s the most infuriating and exasperating thing.”

Lois Greste said both the Australian government and Foreign Minister Julie Bishop had done everything possible to help her son.

“She (Julie Bishop) has done absolutely everything that she can possibly do in speaking to all the ministers and everyone else,” Lois said.

The family didn’t have “any lines of communication with Julie Bishop’s department”, Juris added.

He earlier told ABC Radio his son was still being denied access to his defence lawyer.

Mike Greste, who is in Cairo to support his brother, has expressed disbelief about the bail ruling.

“I’m beyond baffled. I’m finding it extremely difficult to the point of impossibility to make any comprehension of the whole process,” he told reporters outside the court.

Prosecutors insist Greste and other jailed Al Jazeera journalists colluded with the Muslim Brotherhood, now designated a “terrorist” group, and falsely sought to portray Egypt in a state of civil war.

The Al Jazeera trial, in which 20 defendants stand accused, has sparked an international outcry and fuelled fears of a media crackdown by the military-installed authorities.