Australian Immigration Minister Kevin Andrews said on Sunday it was "suspicious" that the Indian doctor held over failed UK bombings had left the country so quickly after charges against him were dropped.
Andrews said Mohamed Haneef's departure from Australia after he was released from custody made the 27-year-old Muslim look more suspicious. "If anything, that actually heightens rather than lessens my suspicion," he said.
Andrews also ruled out reinstating Haneef's visa.
Haneef, whose second cousin Kafeel Ahmed was allegedly involved in last month's failed bombing attempt on Glasgow airport, was detained on July 2 as he attempted to leave Brisbane on a one-way ticket to India.
He was held without charge for several days under tough new anti-terror laws before being charged with one count of "reckless" support for a terrorist group.
But that charge was dismissed on Friday after the country's top prosecutor ruled there was insufficient evidence to support a case. Andrews had already cancelled Haneef's visa on character grounds and on Sunday said he saw no reason to alter his decision.
"His visa's been cancelled and unless there is some overturning of that by the Federal Court, it's my indication that that visa will remain cancelled," Andrews said.
"Nothing has changed in terms of the circumstances in which I had to make a decision concerning Dr Haneef."
On Saturday, Andrews said he would seek to release the confidential police material on which the decision to suspend Haneef's visa was based.
Haneef left Australia in the early hours of Sunday, bound for Bangalore where he will meet his month-old daughter for the first time.
His lawyers have already lodged an application for Haneef's work visa to be restored and said their client held no grudge against Australia and would return to continue working at the Gold Coast Hospital if allowed.
"He doesn't hate Australia. He would come back if he had the opportunity," lawyer Peter Russo, who is travelling with Haneef, told AFP via telephone from Bangkok airport.