Three al-Jazeera journalists jailed in Egypt last month for up to ten years on charges of aiding a "terrorist" organisation will appeal their convictions, according to the family of imprisoned Australian journalist Peter Greste.

Mr Greste, an award-winning foreign correspondent, was detained in December together with al-Jazeera English Cairo bureau chief Mohamed Fahmy, a dual Canadian-Egyptian citizen, and Egyptian producer Baher Mohamed.

The three were convicted of aiding a "terrorist group", the Muslim Brotherhood group of ousted president Mohammed Mursi.

The trial was widely criticised outside Egypt for its lack of evidence and the way it was conducted.

Egyptian President Abdel Fattah al-Sisi quickly dispelled hopes that he might issue a pardon following the trial.

This left the journalists with no choice but to try to win their freedom through the country's criminal justice system.

"Today we wish to announce we intend to appeal the verdict through the formal channels offered by the Egyptian legal system," Mr Greste's younger brother, Mike Greste said.

Mr Sisi, who is the former Egyptian army chief, last year orchestrated the ouster of Mr Mursi, a senior Muslim Brotherhood member, in reaction to mass protests against his rule.

The brotherhood has since been banned and declared a terrorist organisation.

Mr Mursi's removal was followed by a security crackdown on Islamist activists and some media outlets, including the Qatar-based al-Jazeera network.

Cairo has rejected the condemnation as "interference in its internal affairs", but Mr Sisi said this month that he wished they had been deported, not tried.

The conviction and imprisonment of the reporters has sparked a global campaign by rights groups and media organisations to win their freedom and intensified criticism of the government in many western capital.

Mr Greste, in a statement released by his family today, said he drew strength from the campaign as he waits out the appeal in Egypt's notorious Tora Prison.