An Egyptian court that jailed three al-Jazeera journalists for alleged ties with Islamists said on Tuesday that "the devil guided" the group to spread false news defaming the country.

Australian journalist Peter Greste, Egyptian-Canadian Mohamed Fadel Fahmy and Egyptian producer Baher Mohamed were convicted in June of aiding the blacklisted Muslim Brotherhood and spreading false news that portrayed Egypt as being in a state of "civil war".

Greste and Fahmy received seven-year terms, while Mohamed was jailed for 10 years, in a case that sparked international outrage.

Eleven defendants tried in absentia, including one Dutch and two British journalists, were given 10-year sentences.

"The defendants took advantage of the noble profession of journalism … and turned it from a profession aimed at looking for the truth to a profession aimed at falsifying the truth," the court said in a statement explaining its verdict.

"The devil guided them to use journalism and direct it toward activities against this nation," it said.

Since the army ousted Islamist president Mohamed Morsi in July 2013, the authorities have been incensed by the Qatari network's coverage of their deadly crackdown on his supporters.

They consider al-Jazeera to be the voice of Qatar, and accuse Doha of backing Morsi's Brotherhood, as the emirate openly denounces the repression of the movement's supporters which has killed more than 1,400 people.

Sixteen of a total of 20 defendants in the trial were Egyptians accused of belonging to the Brotherhood, which the authorities designated a "terrorist organisation" in December.

Foreign defendants were alleged to have collaborated with and assisted their Egyptian co-defendants by providing media material, as well as editing and broadcasting it.