Members of Darwin's defence community are devastated after the death on Monday evening of Australian Army Corporal Brendan Hannam in a rollover that injured five other soldiers at a bush training area, south of the city.

The Australian Defence Force (ADF) has committed to conducting a thorough investigation into the incident that killed the 28-year-old, who was a passenger in a troop carrier that crashed at the Mount Bundey Training Area.

Darwin-based Timor-Leste peacekeeping veteran Sam Weston said the death had hit the local defence community hard.

"It's heartbreaking" he said.

"The families and the veterans are feeling it."

Mr Weston said he trained at Mount Bundey many times in "very hot, dry conditions in an area full of very high grass" and all defence members were aware the training ground had very challenging conditions.

Mr Weston said Corporal Hannam's death was a tragic reminder of the hazards of military training.

"There's been so many of these incidents over the years, but I think unfortunately when you put on that uniform, this is what you sign up for, sadly," he said.

"Does it happen too often? Sure, but also we want our troops ready to rock if we need to serve on operations."

Fellow Timor-Leste veteran Shane Pascoe-Bell served in Australia's parachute infantry.

"This death is tragic," he said.

"I've lost a close personal friend of mine to a parachute training accident this year as well, not up here in the Top End, but in another state, and I know the soldiers out there at Mount Bundey are going to be feeling gutted."

Mr Pascoe-Bell said when he trained and prepared for deployments at Mount Bundey, safety was a high priority for the ADF, with measures including safety officers trailing troops in training.

"You need a lot of safety, but it's also a role that you are preparing to be put into a real-world environment where there is no safety," he said.

"You've got people at the opposite end of your training in real time trying to end your life, so it's got to be as realistic as possible."

A previous Mount Bundey death

A member of Iraq and Afghanistan veteran Adam Giuliani's unit died from heat stroke while training at Mount Bundey in 2004.

The Northern Territory Coroner later found senior ADF commanders had ignored heat danger warnings.

"The conditions out there were extreme, and he was a young soldier, he had just got back from the first deployment of the Two Cavalry in Iraq and it impacted our squadron hard," Mr Giuliani said.

He said the Mount Bundey terrain was harsh and changed after every wet season.

"In the dry season, the bull dust can be very thick which decreased visibility a lot," he said.

"On the flood plains, because of the amount of water coming off Arnhem Land in the wet season making creeks flow quite fast, created erosion and the conditions changed from season to season."

Mr Giuliani is still being treated for multiple injuries sustained during a non-fatal rollover while his Army convoy was speeding through Baghdad to avoid attack.

"The driving conditions and the tactics over there were totally different to what we'd experienced in Australia, it was all about speed because that provided protection," he said.

"I had a rollover that was 90 metres long and the vehicle flipped three times end to end, all the crew and passengers were okay except for two, and no-one was killed, but when 13 tonnes falls on your head it does hurt."

Balancing safety and realism

The former NT Branch President of the Council of Australian Veterans said the Defence Department appeared to have responded to several fatal military vehicle rollovers in Australia and overseas in recent years by improving safety, including by providing soldiers travelling in them with body armour.

He said in the past just convoying without wearing body armour would leave him and other members covered in bruises.

"They've made huge steps in regards to the safety of personnel travelling in armoured vehicles, there's now cross-harnesses," he said.

"The main thing when you're training is the fatigue, accumulated with the heat, particularly if vehicles don't have climate control in them.

"But we need to train in those sorts of conditions to experience it and to learn how to deal with those things."

Australian Defence Association executive director Neil James said he believed the Defence Department had improved its training safety, but finding the correct balance was difficult.

"The defence force has quite strict safety precautions," he said.

"But it's always a balance between the realism of the training and the safety and if you make the training too simple and too controlled by safety measures, then you're just risking more deaths in combat.

"It's a very, very difficult equation and I don't think they'll ever get it right."