The former NSW Police deputy police commissioner, with extensive experience as an international war crimes investigator, said support systems for veterans had "struggled to keep pace with the nature of modern warfare - and modern life".

He promised to use his "investigators mindset" in his approach to the inquiry and forensically examine and expose issues identified by the inquiry.

"While I cannot say I have felt the impact of suicide, I have walked the ground in conflict zones," Mr Kaldas said.

"I have some insight into the environment in which our defence force operates, and the difficulties faced by those re-assimilating to Australian life."

Mr Kaldas said he and his fellow commissioners, former Queensland Supreme Court Justice James Douglas QC and psychiatrist Peggy Brown, recognised the magnitude of their task.

Every death by suicide was a "tragic event' and there was an over-representation of defence and veteran deaths by suicide in Australia.

"This royal commission is united in its belief that our work presents a once in a generation opportunity to ensure that Australia does all it can to support and reduce the impacts of service on military personnel, veterans and their loved ones."

The first two weeks of hearings in Brisbane will focus primarily on veterans and bereaved families directly affected by suicide.

The commission has received more than 600 submissions, almost half of them from Queensland which is home to a high proportion of veterans and Australia's defence community.

The inquiry will relocate to Sydney early next year where the commissioners will conduct further hearings before it travels to various capital cities across the nation.

The commission's nine-page terms of reference also calls for the examination of contributing risk factors including pre-service, training and deployment, transition, separation and post service issues.

This will include a forensic review of the departments of Defence and Veterans' Affairs, along with the Australian Defence Force, including how personnel are recruited, their housing and finance arrangements, as well as the military's organisational culture.

The commission is due to deliver an interim report on August 11, 2022, and a final report on June 15, 2023.

The inquiry is the latest in a line of inquiries held since 2007 into Australia's veteran suicide crisis. But it is the first with the extraordinary powers of a royal commission, tasked with making lasting and fundamental changes that put in place proper support systems for veterans and their families, especially as veterans transition into civilian life .

The preceding inquiries have identified a raft of challenges for veterans after active duty: significant trauma, a lack of support for those leaving service and re-entering civilian life, and institutional hurdles veterans must overcome to get help through the Department of Veterans' Affairs.

As the commission started, the Defence and Veterans Legal Service is providing free advice for those considering taking part.

"Sharing information with a Royal Commission can be a daunting prospect, especially when that information is lived experience of suicide," the service's senior project officer and former defence member Jasmine Stanton said.

"The Defence and Veterans Legal Service has been set up to support ADF personnel and veterans, as well as their families, carers and supporters, to safely navigate this process and any legal issues, and to get follow up support if they need it."

The service is independent from the Royal Commission, the Department of Defence, and the Department of Veterans' Affairs, and delivered by Legal Aid Commissions nationwide.

The Defence and Veterans Legal Service can be contacted on 1800 33 1800 and at defenceveteranslegalservice.org.au

Lifeline 13 11 14

Open Arms 1800 011 046

Australian Associated Press