The Covid-19 pandemic twice forced the cancellation of the yearly public remembrance event at a hilltop memorial site in Villers-Bretonneux in the Somme region of France.

Bagpipes and didgeridoos were played Monday at dawn in the presence of several hundred Australians who had made the round-the-world trip to pay their respects.

"As a mother I am grateful that my sons don't have to go through this," said Vera Waldby from Perth in western Australia, who was visiting with her husband and family.

"There's still war raging in Europe a hundred and some years later, it reminds us that peace is not a given, and it's sobering to think that young men are still being conscripted," said her son, Jordan Permaine, 25.

Around 700 people attended the ceremony, down from around 1,000 in pre-Covid years, according to the Australian veterans' affairs ministry.

Of the 295,000 Australians who came to fight on the Western Front, some 46,000 died -- huge losses for the young nation, where the sacrifice remains deeply ingrained in the national identity.

Australian troops achieved a breakthrough in Villers-Bretonneux when they pulled off a major counter-offensive against German troops alongside British and French forces.

The audacious operation stopped a German advance that would have otherwise swept on to nearby Amiens, a strategic city for allied forces.