Not so simple when you take into account he already claimed if he was returned to Iran he would be executed. Thanks to the UN we aren't able to return criminals to their country of origin if their lives are in danger.
Yes, UN treaties can have the effect of trumping national law.
But if it means public safety vs. observing a treaty, better to send them back, After all he promised to abide by the laws of Australia when he entered as an immigrant, anyone who breaks that promise and is convicted should be shown the door. Send them back.Even if they claim political persecution as a basis for admission to Australia, they failed or refused to keep their end of the admission bargain, and to boot work to recreate an Islamic State in Australia.
Hasta La Vista , baby!