Championed by the organisation Stand Tall for PTS, the Lightning Bolt Convoy aims to shed light on a condition that affects more than 1 million Australians by making the 2322-kilometre journey from Brisbane to Melbourne.

The group's chief executive, Tony Dell, said: "I think all Australians need to recognise the fact that our brave military and our first responders are helping their fellow Australians every day of the year."

Mr Dell, a Vietnam War veteran and former Australian Test cricketer, wants to break down the stigma surrounding post-traumatic stress, which affects not only affect military personnel but also emergency service officers, doctors, nurses and SES volunteers.

He called on corporate Australia to help rehabilitate those suffering by getting them back into the workforce.

"I don't like the fact that they're sitting at home, taking their medication. Part of what we want to do is get more research going and work out ways that we can help and get them back into our society again because they're good people," Mr Dell said.

The Australian Defence Force threw its support behind the cause, with Chief of Army Lieutenant-General Angus Campbell addressing the convoy on Tuesday morning.

"It's not just an issue the military are dealing with but our entire community are. Without acting on it, without being part of a solution it can be debilitating. We want to be part of that solution," the general said.

"We want to do more than just talk about post-traumatic stress and destigmatise it. We are about action."

General Campbell urged those in the armed services to encourage colleagues and families who were not well to seek help early.

"We encourage people to speak up, to acknowledge a need and seek assistance," he said.