Prime Minister Kevin Rudd is taking the salute at the Australian War Memorial as hundreds of veterans march onto the parade ground.
Mr Rudd attended the dawn service in Sydney earlier on Friday before travelling to Canberra for the main national ceremony.
He was greeted at the war memorial by its director Steve Gower and council chairman, the former defence chief, General Peter Cosgrove.
Mr Rudd will give the commemorative address.
"The national ceremony remembers all who have served, their achievements service their country, and particularly commemorates those whose name appears on the Roll of Honour as having made the supreme sacrifice," Mr Gower said in a statement.
Mr Rudd paid tribute to those who lost their lives in the service of Australia.
"We stand here today in this avenue of heroes, this avenue called Anzac, this avenue with its monuments of steel and of stone, silent still but speaking to us softly with the voices of 100,00 souls, each one of them with their name etched with care on the walls of this great memorial which stands behind us, each one of them the name of a precious life cut short through service to the nation," he said.
"For they were the best of us."
Mr Rudd said it wasn't just the 100,000 whose lives were lost, but the million or more who had gone to war and whose lives were forever changed, as were the lives of their families.
He said he had met some such families on Thursday at the national service in Sydney commemorating the loss of HMAS Sydney with all 645 hands in 1941.
"I met widows married barely a year before Sydney was lost. I met sons and daughters who never knew their fathers because Sydney went down before they were born," he said.
Mr Rudd mused on what the 100,000 men and women who have died in war would say to us today, if they could.
"What is it about their stories that wrenches us still, fully 90 years after the armistice that ended the war to end all wars?
"I think it is this.
"That whatever the comforts of our modern age, whatever its distractions, and whatever its disillusionments, there is something unique about this land Australia and the ideals for which we Australians stand.
"That this is a place of unparalleled beauty, that we are a good people who want for the good of others, that we stand for a deep sense of liberty for which our forebears fought and which should never be surrendered, whatever the cost.
"That we are a people who by instinct cannot stand idly by and be indifferent to the sufferings of others.
"A people with a sense of the fair go for all carved deep into our national soul.
"A people also alert to the needs of our friends and out allies."
These were the values that summoned forth the sons and daughters of Anzac during the last century, he said.
"It is this, I believe, that touches us afresh each new Anzac morning."
