Joel Fitzgibbon reveals the moment he received the call about his son's fatal parachuting accident

Former Defence Minister Joel Fitzgibbon has revealed the heartbreaking moment he received a phone call telling him his son had been in a parachuting accident which would later claim his life.

Lance Corporal Jack Fitzgibbon, 33, died on March 6 after an accident at the RAAF Base in Richmond, about 50km north of Sydney.

Jack suffered critical head injuries and was rushed to Westmead Hospital, where he later succumbed to his injuries. 

Mr Fitzgibbon, who held the position of Australia's defence minister from 2007 to 2009, struggled to fight back tears as he candidly spoke about his son's death, saying his heart was 'still breaking'.

In an interview with Sky News host Erin Molan, who was also at times in tears, the father said receiving the call was 'the worst moment of my life'.

He'd first been told about the accident while at a restaurant in Sydney and was trying to stay optimistic his son may pull through.

He then received another call from Deputy Prime Minister and Defence Minister Richard Marles when he was on his way to Westmead Hospital

'(I was) trying to think the best but when Richard Marles called me about halfway out there (to the hospital), you know, having made those calls myself, I knew that for the minister, to be advised it was very, very serious,' he said.

'I used to be making these calls, never expecting to be receiving one.' 

It is understood Jack's parachute failed to open during a training exercise with the 33-year-old using a knife to try and free himself in order to deploy his reserve chute. 

The knife was found at the ends of the qualified parachutist's fingertips after he hit the ground following the 14,000ft jump. 

Mr Fitzgibbon said he was 'comforted' by the fact his son died doing something he loved and lost his life in service for his country.

'The Fitzys are nothing if not tough and resilient, well get through it, we're tough,' he said.

'Two weeks on we're laughing more than we're crying.'

He also opened up about meeting another grieving father at a Commando Welfare Trust.

'At one point in the conversation, I realised that it seemed to me like he lost his son some time ago. And I asked him, ''when did you lose your son?'' ''15 years ago'',' he said.

'And he was still shattered. So, that gave me a bit of a fright,' Mr Fitzgibbon said.

The former defence minister said he was never worried about Jack 'jumping out of aeroplanes' and was more cautious of what his son would get up to with his mates.

'I mean your son is jumping out of aeroplanes at 24,000 feet, it doesn't seem very rational but you convince yourself he'll be okay,' he said. 

'His mother worried more than I did but not excessively but of course he'd always [say] you know, ''it'll be alright mum''.

Through tears, Mr Fitzgibbon said he would miss texting Jack during the footy, with both father and son avid followers of the Newcastle Knights. 

He said he'd lost interest in the things he once shared with Jack.

'I'm sure that will come back. But texting him, that opportunity, will never come back,' Mr Fitzgibbon said.

When asked if he'd looked back through texts with his son, he wiped away tears as he said 'yes'. 

Inquiries are currently being made into the cause of Jack's death.

'We're not going to be an angry family obviously we sort of are embedded in the defence family ourselves,' he said. 

'We owe it to Jack and those who will still jump or are still jumping to ask the hard questions.

'He'll be forever on our minds. We don't need a birthday or something significant (to remember him).'

Following Jack's death, Mr Fitzgibbon provided an emotional statement to Acting Special Operations Commander of the Australian Defence Force, brigadier James Kidd, in remembrance of his son. 

'We are devastated and heartbroken by the loss of our wonderful Jack,' he wrote. 

'Serving in the special forces was Jack's dream job and we take comfort from the fact he died serving his nation.

'Our lives will never be the same without Jack, but we will always remain proud of him and his many achievements.' 

Jack leaves behind his sisters Caitlin and Grace, his mother Dianne and father Joel.