Australian Muslims should publicly disavow "belligerent" verses of the Koran to weaken the moral conviction terrorists say the holy book gives them, a judge has said while jailing two Sydney terror-plotters.

"Terrorists' reliance on verses of the Koran to support an Islamic duty of religious violence has been seen with more or less clarity in a number of NSW and Victorian cases," Justice Des Fagan said in the NSW Supreme Court on Thursday.

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"If the verses upon which the terrorists rely are not binding commands of Allah, it is Muslims who would have to say so.

"If Australian followers of the religion, including those who profess deep knowledge, were to make a clear public disavowal of these verses, as not authoritative instructions from Allah, then the terrorists' moral conviction might be weakened."

Sameh Bayda and Alo-Bridget Namoa, both 21, were found guilty in October of conspiring between December 8, 2015 and January 25, 2016 to do an act in preparation for a terrorist act

AAP

The couple, whom Namoa described as a jihadi Bonnie and Clyde, can apply for parole immediately, as the judge imposed sentences which have already expired because of the time served since their arrest.

Bayda was jailed for four years, with a non-parole period of three years, which expired on January 25.

Namoa was jailed for three years and nine months, with a non-parole period of two years and 10 months, which expired on January 22.

The couple's phones contained a vast amount of extremist material, including graphic images and videos of beheadings and soldiers carrying Islamic flags.

They also included videos of sermons delivered by Islamic scholars, quoting Koran verses which "unmistakably instruct the believers to undertake jihad in pursuit of universal Islamic dominance", the judge said.

"As seen in this and numerous other prosecutions, the hostile verses (in the Koran) are inspiring serious crimes," he said.

He noted that jihadi propagandists and terrorists "consistently invoke belligerent verses of the Koran".

The judge accepted Bayda was inspired by jihadist propaganda to commit a violent street robbery, with two friends, of two non-Muslims on New Year's Eve 2015.

"Some of the material on (his) devices urged Muslims to attack and plunder Western civilians in their own countries in furtherance of their religious duty," he said.

Bayda said he only told Namoa he was carrying out a suicide attack to get her to feel sorry for him and accept his marriage proposal.

They married in an Islamic ceremony before the planned "attack" and he ultimately backed out of the robbery.

The judge found Bayda had exaggerated to Namoa what he planned to do and she could have been taken in by his false boasting about a suicide mission.

Both were 18 at the time and "demonstrably immature for their age".

He accepted they had renounced their fanatical beliefs and were genuinely remorseful.

The judge said it was up to the state parole authority to decide if they would be released.