A young Australian soldier who died in the Northern Territory training to serve his country is being remembered for his larrikin spirit.
Private Jason Challis was killed during live fire exercises at the Mount Bundey Training Area, about 100km southeast of Darwin, on Wednesday afternoon.
His heartbroken family said they will never forget his loving, larrikin spirit, and added his his cheekiness and loving ways will stay with them forever.
"Our beautiful boy has gone," Private Challis' family said in a statement.
The family said Private Challis' personality delighted and brought people together.
"Everyone he met loved him ... Jason was the best son, step-son, brother and mate you could ever ask for," they said.
"Rest in peace, our darling Jason, we love you forever. Until we meet again."
The digger, aged in his 20s and from Geelong, was shot in the head during a military drill, was treated at the scene and flown to a Darwin hospital, but he died of suspected heart failure.
Private Challis' platoon comrades have been praised for their efforts to save his life.
Veteran and federal Labor MP Luke Gosling said troops, combat medics and air medical staff never gave up on him.
"The soldier's mates responded immediately and superbly with first aid," he said.
Mr Gosling says those involved are receiving psychological and pastoral support.
"It's obviously very traumatic for them," Mr Gosling told AAP.
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 Australian Defence Force has suspended training activities for its combat brigades across the country to review safety procedures.
It comes less than a week after a 21-year-old troop was killed by a falling tree branch during training near Rockhampton in Queensland.
Three Townsville soldiers were also injured earlier this month after the tank they were travelling in hit a tree.
The Chief of Army is deeply concerned by the events, which he says are fundamentally at odds with the responsibility Defence holds to those who serve.
Lieutenant General Angus Campbell said the army will return to training over the next few days once authorities are satisfied that the necessary protections are in place.
"I have great confidence in our leaders, and our men and women, to work together to reinforce our training standards and return to the level of performance we all expect of ourselves, and our nation requires of us," he said.
"I know that our soldiers will continue to support each other as they confront the loss of their mates."
Defence Association spokesman Neil James said live fire exercises were done under complex guidelines but could never be a perfectly safe realistic exercise.
Live fire training accidents were comparatively rare but happened about every 15 to 20 years.
Investigations by NT and QLD police and coronial authorities into both fatalities are ongoing.