An American who had lived as a fugitive in a small far north Queensland town for three decades has agreed to leave the country, after spending three months in immigration detention.

Paton Eidson was arrested at his house in Julatten in May, leading to an outpouring of support from his community, as well as from local MPs Warren Entsch and Bob Katter.

The 72-year-old entered the country in 1986 with his wife and young daughter under false passports, allegedly to avoid prosecution for his involvement in a cannabis ring.

He said he was charged with conspiracy to import marijuana by US authorities in 1991, for events alleged to have taken place in 1985.

Mr Eidson told the ABC that he had now agreed to a deportation order, and would leave the country at the end of August.

"I'm tired of being in here ... my life is just slipping away from me," he said.

After advocacy from Liberal MP Mr Entsch, Mr Eidson was told that after he returned to the US and sorted out his paperwork, an application for permanent residency would be fast-tracked.

Mr Eidson with his late wife Sonja. ( Supplied: Paton Eidson )

According to him, a letter from Immigration Minister Peter Dutton to Mr Entsch reads: "I undertake to grant Mr Eidson a permanent visa, subject to Mr Eidson having been of good character in the intervening time.

Mr Eidson said: "On that basis is why I have accepted the terms and voluntarily agreed to go back [but] it comes down to trusting them."

He said he would need to spend up to eight months in the US before he would be in a position to apply for an Australian visa.

Mr Eidson thanked Mr Entsch and Mr Katter, as well as the community of Julatten for their support.

Eidson worried about own health

Mr Eidson, who has emphysema, said he had been in hospital twice since his arrest, for eight and nine days at a time.

It is understood that as a result of an assessment of his fitness to fly back to the US, he will be required to travel with two nurses and remain on a continuous oxygen supply for the entire flight.

Paton Eidson served in the US Coast Guard in the 1960s. ( Supplied: Paton Eidson )

"Contrary to what you are told to do on a 17-hour flight, [which] is get up and move around … I'm required to stay in the same spot," he said.

"There have been many documented cases up to 72 hours after a flight of people developing a blood embolism … of course things like that worry me."

He claimed the health assessment was made by a doctor in Sydney after reading his case files, and that "there's a whole lot of other issues that should've been considered that I don't think were addressed".

'I've tried to be a good Australian'

Supporters of Mr Eidson were quick to rally behind him following his arrest, offering glowing testimonials.

Friend Michael Gabour said at the time of Mr Edison's arrest that he was "a man of integrity and principle".

"He is a stalwart of the community and has carried his weight the entire time he has been in Australia," he said.

Others in the community described him as an "integral part of the community in Julatten", and "a close family friend that I love dearly".

Mr Eidson said he had always "tried to be a good Australian".

"The judge made the statement at my trial that he had never seen such a glowing list of character references, except once in a case in Townsville where the lady wrote them herself," he said.

"The courtroom was full of people, of supporters; it was quite touching."

He and his late wife were jailed in 2012 for the passport fraud, a fact that led supporters to complain he was being punished twice for the same crime.

The Immigration Department said it would not be appropriate to comment on an individual's circumstances.