A would-be teenage terrorist has been jailed for at least 14 years for planning an attack in Sydney as an 18-year-old.
Tamim Khaja, now 20, believed he had "a sacred duty" to carry out "appallingly wrong" attacks, Justice Desmond Fagan told the NSW Supreme Court on Friday.
Khaja pleaded guilty to doing an act in preparation for, or planning a terrorist act, and had begun to scope out potential target buildings in Sydney including the Parramatta District Court precinct and Timor Army Barracks.
Justice Fagan sentenced Khaja to a maximum of 19 years imprisonment with a non-parole period of 14 years and three months.
The judge rejected a submission from Khaja's lawyer Ian Temby QC he should recuse himself from sentencing because of a perceived bias against his client.
Mr Temby had argued comments made by the judge during earlier hearings regarding previous terrorist operations in Australia could lead members of the public to think Justice Fagan had an apprehension of bias against Khaja and the Islamic faith.
"I find that an astonishing submission," Justice Fagan said.
He repeatedly ensured the court he had no such bias and went to pains to stress the religion of Islam was not on trial.
Khaja himself had said he was motivated not by watching YouTube videos but "straight from the verses of Quran".
According to court documents, Khaja spoke at length with two undercover police officers about his plans.
In May 2016, he met the pair at Parramatta and they drove to the car park of Parramatta Stadium.
"For an attack like this is taken in Australia akhi (brother), it would weaken the Australian government so much," Khaja said.
"So that's why I am saying when I say maximum fire, I mean to take down as many of them down as I can, and at the end when I see that there's too many I will take myself with them as well."
Khaja had "a stable and supportive upbringing" with his family, who had migrated from Afghanistan in 1993 and identified as moderate Sunni Muslims, the court heard.
Nonetheless, he had become radicalised, Justice Fagan said.
"He expected his actions would encourage others of the same mind to undertake similar atrocities, leading to police and security services being overwhelmed, the institutions of constitutional democratic government being weakened, and the Australian people being forced to live under Islamic Law."
