British human rights lawyer Amal Clooney claimed in an interview published on Saturday that she was threatened with arrest in Egypt after identifying flaws in the judicial system that later contributed to the convictions of three Al-Jazeera journalists.

Clooney, a rights lawyer who married Hollywood star George Clooney in a lavish Venice ceremony last year, helped compile a report for the International Bar Association in February 2014 that raised questions about the independence of judges and prosecutors in Egypt.

"When I went to launch the report, first of all they stopped us from doing it in Cairo," she told the Guardian newspaper.

"They said: 'Does the report criticise the army, the judiciary, or the government?' We said: 'Well, yes.' They said: 'Well then, you are risking arrest,'" said Clooney, who is one of the lawyers representing one of the trio of Al-Jazeera reporters currently detained in Cairo.

The report, based on a fact-finding mission made in mid-2013, warned about the wide powers that ministers had over judges and highlighted a record of selective prosecutions.

Supporters of the three Al-Jazeera journalists, who were detained in December 2013 and accused of spreading false information and aiding the blacklisted Muslim Brotherhood, say the charges were politically motivated.

One of the recommendations in Clooney's report was to end the practice that allows Egyptian officials to handpick judges in certain politicised cases.

"That recommendation wasn't followed, and we've seen the results of that in this particular case where you had a handpicked panel led by a judge who is known for dispensing brutal verdicts. And this one was no different," she said.

Egypt's top court on Thursday ordered a retrial of Australian Peter Greste, Egyptian-Canadian Mohamed Fahmy and Egyptian Baher Mohamed, but kept the journalists in custody pending a new hearing.

Fahmy -- whom Clooney represents -- and Greste are seeking deportation, while Mohamed's wife said she was looking at ways to get her husband out of Egypt.

Clooney said she hoped that Fahmy's deportation would go ahead "in fairly quick terms", expressing little confidence in a retrial.

"I don't see how the prosecution can proceed again in a trial process even if the judges were to be constituted properly this time around. I don't see how they could fix the lack of evidence," she said.

"We have to continue and double our efforts to achieve his release in other ways. Unfortunately we have to conclude that we can't rely on these Egyptian court processes to achieve a fair or swift result," she said.