Leading Muslim cleric Sheikh Monsour Leghaei is believed to have arrived in Iran after being told to leave Australia.
He was ordered out after the ASIO found him to be a security risk when he applied for permanent residency in 1995.
But neither the security agency nor the government will tell him the reasons behind the decision because he's not an Australian citizen.
“I'm leaving peacefully and I will come back peacefully again… someday”, he said to cheers from his supporters, who've led a long campaign in Sydney's west.
They say he's a moderate and a huge loss to Australia.
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Father Dave Smith said, “He's done an enormous degree of work bringing together Christians and Muslims and people of different ethnic groups… it's an outrageous crime against the community.”
He left Sydney with his wife, who has been granted permanent residency, and Australian-born daughter, but his three sons are staying in Sydney.
“We will see the day come when the people that deported my father, my mother, my sister, will depart from their seat; will depart from the world”, Reza Leghaei said,
Home Affairs Minister Brendan O'Connor has defended the government's decision, and has the support of Shadow Immigration Minister Scott Morrison.
The Sheikh's supporters say they've lodged an appeal with the United Nations human rights committee and the government has until 21st October to respond.
