Australians and New Zealanders have stopped to honour servicemen and women past and present at Anzac Day commemorations across the world.
The heart of Sydney stood still at dawn as thousands commemorated Anzac Day at Martin Place, more than a century after Australia's soldiers landed on Gallipoli's shores.
The service marked 102 years since the Gallipoli landings, Australia's first major conflict of World War One, and honoured armed forces past and present for their service.
Close to 20,000 people packed the length of Martin Place on the 90th anniversary of Sydney's first dawn service.
Commander of the Australian Fleet, Rear Admiral Stuart Mayer, gave the Anzac address noting that Australia has lost 102,825 men in war since 1861.
"This morning we don't boast about triumphs or victories," he said.
"We remember the sacrifice of those who were prepared to stand up for someone else, for people that believed that there was something bigger, more important than just their own interests and were prepared to put others ahead of themselves and put their lives at risk of because of those beliefs."
He said the dawn service ceremony was a commitment to always remember those who gave their lives in war.
"It is a promise that adds to the dignity of our nation and that the nation's people would annually recommit to the promise to remember those who have stood in harm's way."
WATCH: Turnbull's Anzac Day message
Rain falls as Canberra gathers to remember
Rain hasn't deterred thousands from making the walk to the Australian War Memorial for the Caberra's dawn service.
The commemoration of the 102nd anniversary of the Gallipoli landing will get under way at 5.30am in the cool Canberra darkness.
Former sapper-turned-Paralympian gold medallist Curtis McGrath, who lost both his legs while serving in Afghanistan, will deliver the commemorative address.
Thousands gather in Brisbane's CBD
Thousands have turned out to commemorate Anzac Day, as families, veterans and other locals came together to take part in the the dawn service in the Brisbane CBD.
Anzac Square was filled and many more filled the Adelaide Street overpass for the service that started at 4.28am.
Queensland Governor Paul de Jersey told the crowd the Brisbane service was one of many "solemn, profound and grateful" gatherings across Australia and New Zealand.
"This occasion engenders huge emotional effect nationally and individually - and rightly so," he said.
The war's initial recruits hoped for adventure and the glory of battle, but this didn't last, he said.
"(Eventually) the war's grim reality was plain for everyone to see," he said.
Queensland Premier Annastacia Palaszczuk also present.
The governor's remarks were followed by the strains of a lone piper, which echoed off the boundaries of the still-dark Anzac Square.
Among those attending was Nate Fealy, 39, of Albany Creek, who spent 15 years in the military before departing as a corporal in 2009.
He told AAP he'd been going to local dawn services since he was a kid growing up in a small NSW town.
"Today is just all about being here for the rest of your mates," he said, medals displayed proudly on his chest.
"It's a special day."
Sea of umbrellas at Melbourne dawn service
A sea of umbrellas has surrounded the Shrine of Remembrance in Melbourne as thousands gather in the rain for the Anzac Day dawn service.
The event is expected to bring 100,000 people to commemorate the 102nd anniversary of the Gallipoli campaign.
Roads around the Shrine have been closed off as police ramp up security at public events.
Victoria Cross recipient Corporal Ben Roberts-Smith has urged Australians to welcome veterans into jobs and society as well as mark their sacrifice in war.
The Afghanistan veteran told the thousands gathered at Melbourne's Shrine of Remembrance for the Anzac Day dawn service of the contribution returning soldiers can make.
"The hard-won character, capabilities and skills that defined them in the field are long-held staples for life," Mr Roberts-Smith said on Tuesday.
He said returning from the trauma of war could be tough for men and women in the armed services, but their skills were invaluable for Australian life.
"(They have) a hands-on understanding of how leadership and team work are shared and optimised," Mr Roberts-Smith, now an executive with the Seven Network, said.
"A deep-seated sense of community and mutual care among the people they work with."
Big crowds attend Adelaide service
South Australians have been urged to come out in force to mark Anzac Day.
Veterans Affairs' Minister Martin Hamilton-Smith says people are encouraged to attend the dawn service in Adelaide or similar services in their local area.
He says 10,000 people are expected to gather at the Adelaide War Memorial as dawn breaks on Tuesday.
"On Anzac Day we honour those who made the ultimate sacrifice. We remember their families and communities, changed forever," Mr Hamilton-Smith said.
"We reflect on all in our community who endure the physical and psychological impact of war, and we take this moment to thank Australia's servicemen and women for their service."
A shower or two has been forecast for Adelaide, while temperatures should be mild for both the dawn service and the annual march.
Thousands pay tribute at NT dawn service
Thousands of people have turned out to Darwin's Anzac Day dawn service, 102 years since the landing at Gallipoli.
About 2000 Territorians gathered in the muggy pre-dawn service at the Cenotaph to commemorate the ill-fated landings by Australian and New Zealand soldiers.
NT Chief Minister Michael Gunner, some of the last surviving World War II diggers, young troops fresh from deployments in Iraq and about 100 US Marines currently serving in the NT capital were in attendance.
Light Horse honoured at Gold Coast service
A company of 12 light horseman has led veterans into the Anzac Day dawn service on the Gold Coast as the centenary of the successful charge by Australian cavalry in the World War One Battle of Beersheba was honoured.
An estimated crowd of 15,000, including former prime minister Tony Abbott, gathered in the shadow of Elephant Rock on Currumbin, which was lit red for the service.
The service, one of the biggest regional services in Queensland, began with a didgeridoo being played on the base of the rock and a lone piper then took over from the top of the rock.
Large Anzac crowd at Perth's Kings Park
Among the thousands attending Perth's Anzac Day dawn service was Vivienne Stewart who was honouring her late grandfather and decorated World War I soldier Frederick Gaze.
The Gazes have a distinguished history of military service.
Frederick's brother Irvine was a fighter pilot and polar explorer who was part of the Shackleton Antarctic expedition and his son Tony was a famous WWII flying ace and Australia's first Grand Prix racing driver.
Ms Stewart was wearing her grandfather's medals, including a Military Cross won for gallantry in the Battle of Hamel on the Western Front.
He returned to Australia and was a farmer at Gnowangerup and died relatively young.
"It is a significant thing for our family, certainly," she told AAP at the service in Kings Park.
"I have been going to dawn services my whole life, either here or in Albany where my grandfather had a beach house and often used to lead the parade.
"It is pretty special, it's important that we all remember the past."
Perth's skyline formed a spectacular backdrop for the city's biggest Anzac Day dawn service at the State War Memorial in Kings Park.
Kings Park is on Mt Eliza overlooking Perth, which holds the nation's final dawn service due to a two-hour time zone difference with the eastern states.
This year holds special significance to WA as it's 75 years since Japan's air attack on Broome during World War II.
New Zealand reflects on Anzac sacrifices
Anzac Day has offered New Zealanders the chance for "thanks and quiet reflection" for those who sacrificed their lives in war, as thousands attended dawn services around the country.
At the Pukeahu National War Memorial Park in Wellington on Tuesday morning, Governor-General Patsy Reddy, in front of a sombre crowd, thanked veterans for their service and commitment to the country.
She referred to the Battle of the Somme in 1917, where New Zealand's casualty figures were almost that of the Gallipoli campaign two years earlier.
"For the bereaved, an Anzac Day service was the nearest thing to a funeral that their loved ones would ever had."
Australian Defence Department secretary, Dennis Richardson, attending his first Anzac day ceremony in New Zealand, paid tribute to all former and current members of the defence force.
"This is a day of thanks and quiet reflection. We are reminded of the debt of gratitude of those who paid the ultimate sacrifice. The bond between New Zealand and Australia is unlike that of any other."
As the ceremony concluded the crowd was invited to lay tributes on the tomb of the unknown warrior.
A National Commemoration Service will be held at the same location from 11am.
The Wellington service was one of many dozens being held around the country on Tuesday.
Governor-General lauds WWII heroes in PNG
Australians will never forget the courage of those who fell in the jungles of Papua New Guinea nor the "national treasures" who survived the worst conditions of warfare.
Governor-General Sir Peter Cosgrove made that pledge as he delivered the Anzac dawn service address on Tuesday at the Bomana War Cemetery near Port Moresby.
This year marks the 75th anniversary of the Kokoda campaign and the Battle of Milne Bay, which formed part of the New Guinea campaign in the Second World War.
Bomana is the largest war cemetery in the Pacific with close to 4000 graves, mostly Australian.
"Those who gave their lives and lie here are always in our hearts," Sir Peter told the crowd.
"Their deeds, their sacrifices and the battles they fought have shaped us."
He reflected on the pivotal role Australian troops played in PNG halting the Japanese advance, after Singapore fell and northern Australia was bombed.
"They were courageous and enduring in some of the worst conditions warfare can demand," Sir Peter said.
"Many would fall here in the jungle, away from the wide brown land they loved, but were destined never to see again."
He paid tribute to the bravery of Corporal Jack French, awarded a Victorian Cross for single-handedly taking out three enemy machine gun posts during the Battle for Milne Bay.
"Although badly wounded he continued to advance until fatally shot," Sir Peter said.
Opposition Leader Bill Shorten and his wife Chloe also travelled to PNG for Anzac Day commemorations.
"As the sun rises on these white stones we remind ourselves each one stands for a son, a father, a brother - someone who loved, who was loved and who never came home again," Mr Shorten told the dawn service at Bomana.
"In our nation's darkest hour, when Australia faced its sternest test, they paid the highest price."
An estimated 625 Australians were killed on the track and more than 1600 were wounded. Casualties from sickness exceeded 4000.