Members of the defence force, emergency services and the public took part in Warrnambool's Walking Off The War Within, which is hosted in memory of returned soldier and firefighter Nathan Shanahan.

Nathan was a fierce advocate for mental health, walking over 400 kilometres from Mildura to Adelaide in April 2015 with a 20-kilogram pack to raise awareness and funds for PTSD and depression.

He took his own life in December the following year.

Nathan's dad John Shanahan said Walking off The War Within continued the legacy his son started.

He said attendees walked up to 20 kilometres on Sunday carrying 20 kilogram packs, which represented the heavy burden of mental illness.

"This is always a very emotional event but it's great to see so many people all here for the one cause - mental health, which is very close to myself and my family," he told The Standard.

Mr Shanahan said while the pain of losing his son would always be raw, he'd made it his life mission to advocate for society to be more open about mental illness.

"It's not something we whisper in the corridors or talk about behind the scenes anymore, it needs to be out in the open," he said.

"It's never going to go away and we not only need to talk about it, but put pressure on governments to better fund and manage mental health services everywhere."

About 100 people took part in Sunday's walk with even more taking to the sidelines to show their support.

Warrnambool RSL members were joined by a group from the Hawthorn branch, including Matt French, Patrick Manning and Hawthorn RSL president Eamon Hale.

The trio, who are members of 4th/19th Prince of Wales's Light Horse Regiment, donned their uniforms as they tackled the 20-kilometre trek.

"We are taking part as army reserves so it was important to wear our PT battle uniform," Mr Hale, who lived in Warrnambool as a child, said.

"We've been walking, talking and learning more about each other. Our fourth member is a bit behind us, walking with his dad and that is just a beautiful thing.

"We're sharing the burden together and I think that's the most important thing. We're beyond the point of raising awareness about mental health, we know it's there and it's about working through it together."

Emergency Management Commissioner Andrew Crisp, who worked in Warrnambool as a police officer in the 1980s, also made the trip down from Melbourne for the event.

"Mental health doesn't discriminate and whether you wear a uniform or not, you're a commissioner or in a junior role, everyone has been through tough times and if just one or two people put their hand up and tell their story, today is a success," he said.

Sunday's event was organised by Warrnambool RSL, RSL Active, and Warrnambool and Melbourne Legacy.

The community day included free family-friendly activities, food vans, live music and a sausage sizzle hosted by the Military Brotherhood Military Motorcycle Club.

James Mempham, a Warrnambool RSL Active volunteer and community and peer advisor for Open Arms, said he was rapt with the turn out.

"It's been brilliant and it's only going to get bigger as the day goes on," he said.

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