As jailed journalist Peter Greste marks one year in Egyptian custody on Monday, Foreign Minister Julie Bishop says she remains “mildly optimistic” he will be released soon.

Forty-nine-year-old Greste and his two colleagues, bureau chief Mohamed Fahmy and producer Baher Mohamed, have an appeal date set for New Years Day, with hopes they will be given a presidential pardon.

• Why Peter Greste is set for a ‘very good Christmas’
• ‘Keep fighting,’ Greste urges

In an interview with France 24 in November, Egyptian President Abdel Fattah al-Sisi said the detention of the journalists was “under study”.

The three men are serving jail terms between seven and 10 years for spreading false news and aiding the banned Muslim Brotherhood.

In a letter from his Cairo jail cell released last week, Greste said the case had created global awareness for press freedom.

“We have reignited public discussion and awareness of the vital role that unfettered journalism plays in any healthy, functioning democracy,” Greste wrote.

“As we approach Christmas and the rather inauspicious anniversary of our arrest on December 29, there is a temptation to become morose over our continued detention.”

“But, at the same time, we have changed something fundamental.”