For almost 14 months, their father, Daniel Duggan, has been locked away and held without charge. He's been fighting US extradition on allegations of conspiracy that he says are unfounded and politically motivated.

Mr Duggan's wife, Saffrine, says he's been hold in solitary confinement and she doesn't think he can handle much more.

The NSW family is now pleading for the Australian government to release their dad for Christmas.

The 55-year-old has now spent almost 14 months locked inside a four-by-two-metre cell without charge in Australia, fighting US extradition on allegations of conspiracy he says are unfounded and politically motivated.

"I've been asking the kids what they want for Christmas," wife Saffrine Duggan told the Central Western Daily this week.

"Hazel and Ginger both say 'The only thing on my list is for my dad to come home ... can you please tell Santa to bring him home?' That's heart breaking."

Mrs Duggan said her husband is beyond upset.

"He tries to give the children courage but when I talk to him, and it's just me and him - two adults, two people that love each other - he's not coping at all and he is not going to be able to handle much more in solitary confinement. That's the truth of it," she added.

"He is broken and I can noticeably see a change in his ability to process information, to have conversations."

This week Mrs Duggan and the family published open letters to Prime Minister Anthony Albanese and Attorney-General Mark Dreyfus, requesting he be released on home detention over the Christmas holiday. The say he is not a flight risk and poses no threat to the community.

"At this special time of year, I am writing to plead with you to exercise your power," the letter said in part.

"I beg you to send my husband back to his six children in regional NSW where he belongs at Christmas.

"For Dan, there is no presumption of innocence, no privacy, no dignity, and no reasonable opportunity to actively participate in his own defence. During his time in prison, he has missed so many family milestones, including the tragic death of his mother."

Details of the case remain shrouded in mystery.

Minutes after dropping his children at school in October last year, the former US fighter pilot and father-to-six was arrested at Woolworths by federal police acting on behalf of the FBI.

A 2017 US indictment alleges he conspired to train Chinese fighter pilots and launder money from a flight school in South Africa more than a decade ago, which he denies.

Mr Duggan has not been charged with any crime in Australia. If extradited and convicted he faces a maximum prison sentence of 65 years.

Multiple human right's advocates have criticised the process. A clinical psychologist has described his living conditions as extreme and inhumane". In February an appeal was lodged to the United Nations human rights committee.

"It is very un-Australian, it doesn't follow the human rights of any country let alone Australia," Mrs Duggan said.

"The allegations are clearly political ... Our relationship that we had with China 12 years ago - and that the US had with China 12 years ago - is not the same as now."

The Duggan-family's cattle farm just outside Orange in central western NSW is home to Saffrine, her father Robert and the six children: Molly, Finn, Rory, Jack, Hazel and Ginger.

Mrs Duggan is a photographer and fashion designer, but has almost entirely stopped work to campaign for her husband's release.

"The children have all been in and out of counselling. They're deeply disturbed since this has happened," she said in the lead up to Christmas.

"There's so many tears throughout the evening, they don't sleep in their own rooms anymore. There are constant showings of deep trauma that set in for my children, and they will live with it for the rest of their lives.

"The people that they're really hurting are Dan's kids .... They're taking their father away from them at a time in their life when they need a dad."

The family says they have spent more than $1 million funding the extradition appeal. They say the recent seizure of Saffrine's property on the NSW south coast - which was listed for sale to raise money - has put further pressure on the defence.

Mrs Duggan says support from the Central West community has been one beacon of hope, and appealed for residents to join their campaign. A Change.com petition calling for release had secured more than 20,000 signatures as of publishing.

"I'd like to really thank the people of Millthorpe, Forrest Reefs, and our friends in Orange ... There's a huge amount of support around here and everyone is completely disgusted and confused as to how this can happen," she said.

"People are just amazed that it's happening ... they can't believe it's happening to these, beautiful little children.

"It's happening in Australia right here and right now. Frankly, I'm shocked by our government."