The 33-year-old son of former Hunter MP Joel Fitzgibbon and his wife Dianne suffered critical head injuries in a "two-million-to-one" parachute incident amid Australian Defence Force (ADF) training at Richmond RAAF base on March 6.

He passed away in hospital a day later.

Speaking to the Newcastle Herald, Mr Fitzgibbon said Jack was a unique person, incredibly special and universally loved.

"We have been overwhelmed by visits to the home and messages of support," he said.

"The family home is like a florist's shop, there's enough food in the kitchen to last us for the next five years because people have been so generous."

Mr Fitzgibbon said his family had been touched by the outpouring of support, not only from the Hunter community, but nationally and internationally, from former to current prime ministers, ambassadors and beyond.

"But what has really struck me is that people that never met Jack have been in tears talking to me on the phone," he said.

"Jack was a unique person, obviously from our perspective very special and universally loved, and for that reason I think you will see a very large gathering on Monday.

"He was a very popular guy but also a bit of a larrikin, a larrikin capable of finding trouble."

Lance Corporal Fitzgibbon was born at Maitland Hospital and grew up in Cessnock before later moving to Cronulla.

After completing part of a mechanical engineering degree at the University of Newcastle, he decided it was not for him and enlisted in the Australian Army instead.

Mr Fitzgibbon said he's still not entirely sure what sparked his son's interest in the defence force, but fondly recalled his son insisting on an "army shirt" from the age of three.

"He had a fascination with the army from a very early age, he always had his 'army shirt' on and whenever he'd see an army vehicle of any description he'd say, "there's army" or "here's army" - which was not quite grammatically correct but made it a bit funnier," he said.

"Every year I used to go up to the Singleton Infantry Centre because he'd run out of his last one.

"So nature or nurture, it seemed to be nature in that case."

Mr Fitzgibbon served as the minister for defence from 2007 to 2009, and retired before the 2022 general elections.

He said that from the moment his son entered the Kapooka training base, he loved what he did, going on to receive an award for his work.

Lance Corporal Fitzgibbon eventually became a soldier within the 2nd Commando Regiment, which is part of the Special Operations Command within the army.

He eventually "got his wings", becoming an experienced parachutist with about 90 jumps at altitudes up to 24,000ft, Mr Fitzgibbon said.

"He was an experienced jumper and obviously we're shattered that we lost him because two chutes failed, which we calculate as probably two-million-to-one," he said.

"We're anxious to secure the outcomes of the investigations that are going on, which will determine how such an unlikely event could occur.

"Almost a week on, we remain shattered and heartbroken but it's been a great comfort to us that he died doing something he absolutely loved and in service to his country."

His sisters, Grace and Caitlin, remember him as an "amazing brother" who "knew exactly how to push his sisters' buttons".

"But he was always there for us if we needed anything at all," Grace said.

"We're incredibly proud of him, we've had overwhelming support, but that's to be expected given how much our brother was loved by everyone he met.

"We all miss him very much."

On Saturday, Lance Corporal Fitzgibbon was honoured with a moving tribute from his local rugby league club, the Cessnock Goannas.

The Fitzgibbon family raided his wardrobe, wearing all of the Goanna paraphernalia, shirts and jumpers they could find, standing up on the hill while the Australia flag flew to the sounds of The Last Post.

"Jack loved his footy, his grandfather played for the Goannas, his father played for the Goannas, his uncle played for the Goannas and so did Jack, so that football community is a very important one for us and we really appreciate the gesture," Mr Fitzgibbon said.

Lance Corporal Fitzgibbon lived in Cronulla with his partner Kass and Mr Fitzgibbon said "she's a Fitzgibbon now too".

"We love her, and we're feeling her pain," he said.

A celebration of life will be held for family and friends of Lance Corporal Fitzgibbon on Monday, March 18 at 11am at St Joseph's Catholic Church on Cumberland Street, Cessnock.

The service will not be live-streamed due to ADF protocols, and in lieu of flowers, donations can be made to the Commando Welfare Trust.