Egypt’s president has issued a decree allowing him to deport foreign defendants convicted or accused of crimes, in a move that could affect jailed Australian journalist Peter Greste.

The decree by President Abdel-Fattah el-Sissi was issued on Wednesday night and comes amid international criticism over Egypt imprisoning Greste and two other journalists from the Al-Jazeera English satellite news channel.

The presidency did not elaborate about the decree, which allows extradition whenever the president decides it is the best interest of the country.

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The journalists were convicted of aiding the blacklisted Muslim Brotherhood and falsely portraying Egypt as being in a state of “civil war.”

They have been detained since December 2013 and are awaiting an appeal hearing set for January 1.

El-Sissi previously said he was unable to take action in the Al-Jazeera case until after the final verdict.

In an apparent reference to the Al-Jazeera case last month, el-Sissi said he thinks the ideal way to deal with “transgressions” by foreign journalists would be to deport them.

But Al Jazeera English chief Al Anstey says it’s just another twist and turn in a very confusing and unfair process.

“It defies logic, it defies justice they’re still behind bars after 320 days,” he said on Thursday.

The Al Jazeera boss is in Sydney this week to speak to Greste’s family and campaign for his release.

The trio is appealing against the convictions on the grounds of flawed evidence, which Anstey said bordered on the surreal at times.

“They had videos from other news organisations, family photos, they had the Gotye music video. It was totally irrelevant to the case,” he said.

US President Barack Obama and UK Prime Minister David Cameron have led international calls for their exoneration and rallied for press freedoms.

Anstey thinks those conversations will get louder as the next court date approaches.

In the meantime, he is deeply concerned for the men, who are living in a very confined space and in difficult circumstances.

“They’re living a nightmare every second of every day. They’ve got to be set free,” he said.