The mates of a young Australian soldier who was fatally shot in the head during a live fire training exercise in the Northern Territory have been praised for their efforts to save his life.
Jason Challis suffered severe head injuries at the Mount Bundey Training Area, about 100 kilometres south-east of Darwin, on Wednesday afternoon.
The soldier, aged in his 20s and from Geelong in Victoria, was treated at the scene and airlifted to a Darwin hospital but later died of a suspected heart failure.
Federal Labor MP Luke Gosling said the digger's platoon mates, combat medics, and aeromedical evacuation staff never gave up on him.
"The soldier's mates responded immediately and superbly with first aid," he said.
Mr Gosling, a veteran himself from a military family, says he's grateful the troops involved are receiving psychological and pastoral support.
"It's obviously very traumatic for them," he said.
"It's just a reminder of the danger of the work that they do every day."
Craig Garraway from St John Ambulance NT said Mr Challis was suffering a cardiac arrest and major blood loss when he arrived at Royal Darwin Hospital around 2.30pm.
"I'm led to believe it was a gunshot wound to the head," he said.
The Victorian man's friends have been reaching out to his loved ones with tributes on social media, as several relatives change their Facebook profile photos in his memory.
"Sending you and your fam (sic) heaps of love. This is a tragedy no one should have to face," one person commented.
"Mate, I know there are no words. Condolences from all of us. His duty is done. Rest easy," posted another.
The Australian Defence Force has suspended training activities its combat brigades across the country to review risk assessment processes and training safety management.
It comes less than a week after a 21-year-old digger was killed by a falling tree branch during a training drill near Rockhampton in Queensland.
"The Army and ADF community extends its deepest sympathies to the soldier's family and friends," Defence said in a statement.
"It is a deep shock to the organisation and will be felt by the broader army family."
Defence is expected to release more details as soon as Thursday or Friday, but wouldn't disclose any personal information about the soldier while it provides support to his family.
NT police are investigating and will prepare a report for the coroner.
Defence Minister Marise Payne sent her heartfelt condolences to the soldier's family, friends, and colleagues.
"Whether on deployment or while training, the men and women of the Australian Defence Force undertake hazardous activities to ensure our safety and security," she said.