Saturday marks the 111th anniversary of Australian and New Zealand forces landing on the Turkish coast at Gallipoli on April 25, 1915.
More than 8000 Australian soldiers died during the unsuccessful campaign, which failed to wrest control of the Dardanelles.
Prime Minister Anthony Albanese has attended the dawn service at the Australian War Memorial in Canberra to acknowledge the debt owed to all servicemen and women who have gone to war.
"We give thanks to our veterans for all you have given," he has told the some 35,000 people gethered.
"We thank all Australians serving now, and we thank your families, who take on both the pride and the burden.
"What their legacy proves to us is that even when peace seems elusive, it is always worth fighting for."
As part of the Canberra service, the traditional Maori haka has been performed in war memorial's forecourt.
In Sydney, a small but vocal interjection of booing unfortunately greeted the acknowledgement of Country.
After those disturbing the peace were quieted, a chorus of applause and cheering rang out for an extended period to show support for Pastor and Uncle Ray Minniecon.
Similar disruption was drowned out in Melbourne where Bunurong and Gunditjmara man Uncle Mark Brown delivered his welcome.
Opposition Leader Angus Taylor, meanwhile, has described Anzac Day as something more than an expression of respect and gratitude.
"In remembering our fallen - in reaching into the past - we remind ourselves of who we are as Australians," he says in a statement.
Anzac Day marches in Melbourne and Sydney will begin at 9am AEST, and Last Post ceremonies will be held in the late afternoon.
A Royal Australian Air Force F-35A Lightning II aircraft will fly over the national war memorial during the veterans' march at 9.30am.
Victoria Cross recipient Ben Roberts-Smith has attended an Anzac Day service in Queensland while on bail over war crime charges.
Mr Roberts-Smith denies the accusations.
"Anzac Day is sacred to me and every other veteran," he told the Australian on Friday.
"I will be attending to pay my respects and I encourage everyone else to."
Mr Roberts-Smith has been charged with five counts of war crime murder, alleged to have been committed during his service in Afghanistan as a special forces soldier between 2009 and 2012.
Anzac Day is commemorated each year on April 25 and recognises the more than 1.5 million Australians who have served in wars and peace operations, including the 103,000 who have lost their lives.
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