Mr Turnbull made the pledge in the small French town of Villers-Bretonneux, where Australian troops pulled off a stunning victory over invading German troops and in doing so, altered the course of world history.

As defence force personnel and veterans marched through Australian cities and towns, many led by women for the first time, Mr Turnbull told 8000 people gathered in Villers-Bretonneux that there was one way to properly honour the Aussie victory there.

"The best way to honour the courage and sacrifice of the diggers of World War I is to support the servicemen and women, the veterans and the families of today," he told a moving dawn service in the Western Front town.

The Australian campaign that retook Villers-Bretonneux in 1918, on the third anniversary of Anzac Day, was a defining moment in the war-time history of Australia, and in the forging of the national identity, Mr Turnbull said.

On April 24, 1918, German troops making one last push to win the war overran Villers-Bretonneux, intending to then take the strategically important rail town of Amiens, nearby, and forge on to Paris.

The Germans had broken through an inexperienced line of British troops, and the Australians were tasked with getting it back.

As dawn broke on Anzac Day a century ago, they'd done just that, but at terrible human cost, 2500 casualties from the 3900 Australian men who were ordered to fight.

Almost 3000km away, at Anzac Cove on Turkey's rugged Gallipoli peninsula, thousands stood in silence on Wednesday to remember the scale of the losses there 103 years ago.

The blood of Australian and New Zealand soldiers stained the sand and the sea as they came ashore under a hail of machine-gun fire from the cliffs above, the Anzacs sitting ducks in an ill-fated attempt to take the Ottoman Empire out of the war.

But Home Affairs Minister Peter Dutton said it was from such unfathomable losses that Australia's national identity emerged.

"We feel we know them, the Anzacs. Not only because they fought to defend us, and sacrifice for us, but it is also the power of that sacrifice ... and values they embody and bequeath to us survive to this very day," he told the service.

Back home, Anzac Day parades across Australia looked different this year, amid a concerted campaign to highlight the long history women have had in serving and protecting the nation.

For the first time in many centres, from Sydney to Darwin, women led parades in an effort to broaden public perceptions about the long and varied history women have had in the armed forces, including in war zones.

The By the Left campaign was spawned by women veterans to also encourage more women to celebrate the rich contributions they have made and continue to make, including in combat roles traditionally considered male-only territory.

Nicole Bradley, her service medals pinned firmly to her left shoulder, marched in Brisbane's parade on Wednesday, the first time she's done so despite 22 years of service in the army.

She told AAP that part of her wanted to march in the past.

"But I didn't know where I would march," she told AAP.

This year's campaign for equal recognition left her sure of her place, and she proudly took it.

Australian Associated Press