His violin case still contains grains of desert sand from his time serving in Libya in North Africa.

It's the same sand in which 10 of his mates were buried, after they were killed by a single shell.

One of the last surviving Rats of Tobruk, Mr Semple, who turns 98 next month, reflected on mateship and his experiences in World War II at the Anzac Day national service in Canberra on Wednesday.

"May I humbly say, Anzac Day remains sacred to all of us... let us continue to make reference to the past, but go forward into the future, with honour and courage," he told the service at the Australian War Memorial.

He brought his beloved violin to Canberra from his home in Melbourne, and joked his skill level had waned over the past 75 years.

It had been part of the "entertainment material in the gun pit".

Mr Semple recounted the horrors of trench warfare and how anxiety and fear subsided as experience increased with each engagement.

"Coming under German bombing, and periodic shelling of the position by the enemy, taking refuge in the skinny slip trench, adjacent to the gun pit, holding hands across the shoulders and muttering, if this is it, 'we all go together'," he said.

Western Australia's new governor and former defence minister Kim Beazley spoke of his grandfather's service in the First World War and the scar left on his family.

"I asked my grandmother why she never remarried. Two reasons - there were no young men and there was pride in being a war widow," he said.

Mr Beazley said Anzac Day was not about officialdom.

"Anzac Day is a people's creation, a day for veterans," he told the crowd.

Governor-General Peter Cosgrove, who served in Vietnam and East Timor, and went on to become chief of the defence force, reviewed the parade of veterans marching.

A riderless horse led the march, as 11,500 people watched on.

Acting Prime Minister Michael McCormack was among dignitaries who laid floral wreaths.

This year marks the 103rd anniversary of the landing at Gallipoli in Turkey and the centenary of the Battle of Villers-Bretonneux on the Western Front in France.

Earlier an estimated 38,000 turned out for the dawn service in Canberra.

Colonel Susan Neuhaus became the first woman to deliver the national commemorative address.

The veteran surgeon reflected on a century of severed limbs and broken bodies, and her awe of what those who came before her gave to Australia.

As a girl attending Anzac Day services she did not understand the silence "of half murmured hymns and of old men lost in their own thoughts".

"And yet somehow those stories of service and sacrifice ground themselves into my DNA," she said.

Ann Young travelled from Perth to attend her first dawn service with her daughter Natalie Norbury and granddaughter Matilda.

"It was very good, very emotional," she said.

Australian Associated Press