At the foot of the Carillon a vigil around the Tomb of the Unknown Warrior quietly changed guard every 15 minutes, and would continue to do so until dusk today.
On behalf of US President Barack Obama, Secretary of State Hillary Clinton sent best wishes to New Zealand and Australia.
"Today we pay tribute to all the men and women in the armed forces of Australia and New Zealand who have served with dedication, courage, and sacrifice.''
Around the country thousands of people attended Anzac ceremonies.
RSA chief executive Stephen Clarke said good weather ensured large crowds of veterans, school groups, young people and families.
"The turnouts have been once again huge _ there's great support in terms of remembering our veterans,'' he told APNZ.
"It's fast becoming a rite of passage in terms of making sure that you get to the dawn service. And for a first-timer, it's quite extraordinary. They can't get over how many people turn up.''
In Auckland, the crowd of more than 10,000 far exceeded the expected turnout.
The light was clear with the backdrop of the red-lit War Memorial Museum framing the blue sky as the sun rose.
Mr Key and Labour leader David Shearer attended the service, after which Mr Key flew to Wellington to attend the national service.
In Wellington, the dawn service opened with the loud report of a cannon and a cloud of smoke that lingered around the Cenotaph.
Chaplain Peter Savage led a prayer that paid tribute to the three New Zealand soldiers who have died overseas since last Anzac Day.
"On this Anzac Day there would be so much that we would rather forget, but we dare not forget,'' he said.
"We dare not forget the tragic deaths of three brave New Zealand servicemen since last we met in this way _ Corporal Douglas Grant, NZ SAS, Lance Corporal Leon Smith, NZ SAS, Corporal Douglas Hughes, 1st RNZA.''
Corporal Grant and Lance Corporal Smith were killed last year in separate operations, while Corporal Hughes died suddenly in Afghanistan recently.
In Christchurch, the crowd braved the cold at a ceremony at Cranmer Square attended by Sir Jerry.
A temporary Cenotaph was constructed from pieces of rubble from throughout the city. It was put together by urban search and rescuers, whose ties to the city were forged in the days after last February's deadly quake.
Air Force fly-bys marked the end of dawn services in many centres, with a Hercules plane flying over Auckland services and Iroquois helicopters flying over Otaki, Feilding, Palmerston North, Bulls and Foxton.
Some 400 Defence Force personnel will be serving overseas on operations, UN missions or participating in exercises during Anzac Day.
In Afghanistan, the Defence Force's Provincial Reconstruction Team was to hold dawn services at its headquarters and forward bases in Bamyan province.
The team's commanding officer, Lieutenant Colonel Pete Hall, said the personnel would reflect on those who had made the ultimate sacrifice in the service of their countries.
"It is especially poignant for those of us serving in Afghanistan as we will be remembering those who have been killed in action or died whilst deployed here.''
At Gallipoli in Turkey, more than 10,000 people were expected to attend the Australian-led dawn service, followed by an Australian service at Lone Pine and a New Zealand service at Chunuk Bair.
New Zealanders also turned out for dawn services in Australia, with representatives from the New Zealand Defence Force attending more than 40 Anzac celebrations.
In London, up to 3500 people were expected at a New Zealand-led dawn service at Hyde Park Corner, to followed by a wreath-laying at the Cenotaph in Whitehall and a noon service at Westminster Abbey.
This Anzac Day marks the second since a Defence Force Iroquois helicopter crashed in low cloud at Pukerau Bay, north of Wellington, on its way to a dawn flyover in the capital.
Pilot Flight Lieutenant Hayden Madsen, 33, co-pilot Flying Officer Daniel Gregory, 28, and crewman Corporal Ben Carson, 25, were killed in the crash.
Sergeant Stevin Creeggan, 37, survived but suffered serious injuries.
