Seventy years on from a day that changed the world, Prime Minister Tony Abbott and fellow world leaders have stood with D-Day veterans in France to remember.

Commemorations marking the 70th anniversary of the World War II landings at Normandy began on Friday with Mr Abbott, Prince Charles and British Prime Minister David Cameron among those to attend a moving British morning service.

Joined at the beautiful Bayeux Cathedral by hundreds of ex-soldiers – including seven Australians – who fought in Normandy, those gathered were urged never to forget the sacrifices made on June 6, 1944.

“You who are Normandy veterans remain as witnesses to us of the high price that had to be paid to rid this continent of a terrible and tragic evil,” Right Reverend Nigel McCulloch told the service.

“We owe you and all the Allied forces who took part in this operation a monumental thank you.”

Following the service, Mr Abbott joined the veterans on a walk to another ceremony at the Bayeux Cemetery.

Locals lined the streets in glorious sunshine, applauding the soldiers as they went by while others simply said “thank you.”

Mr Abbott chatted with the Prince of Wales along the way, before stopping at the graves of Flight Sergeant Malcolm Robert Burgess and Pilot Officer Roland Gilbert Ward, two of the 14 Australians killed in battle on D-Day.

Just finished #DDay70 ceremony at Bayeux cemetery – It was privilege to be in the presence of 7 Australian veterans pic.twitter.com/9g0J17lzN9

— Tony Abbott (@TonyAbbottMHR) June 6, 2014

The landings in Normandy, the largest seaborne invasion in history, caught the Germans by surprise and played a crucial role in the Allied victory in the war.

More than 3000 Australians fought in the campaign, mostly in the airforce.

“D-Day was a day that changed the world,” Mr Abbott said.

“It was the beginning of the liberation of Europe that helped set up a post-war world which, for all of its difficulties and problems, has been unprecedented in terms of the prosperity of humanity.

“It is very important that we honour the people who did so much to make this possible.”

Joining Mr Abbott in France were Australian former WWII pilots Stuart Davis, Phillip Elger, Francis Evans, Ronald Houghton, Billy Purdy and Frederick Riley.

All were awarded France’s prestigious Legion of Honour on Thursday night in recognition of their service. They’re joined in Normandy by pilot Robert Cowper who had received his Legion of Honour in 2004.

Later on Friday, Mr Abbott will attend the international ceremony at Sword Beach, near Ouistreham, expected to mark the high point of anniversary events.

Up to 19 heads of state, including US President Barack Obama and Russian President Vladimir Putin will attend.

French President Francois Hollande will deliver a speech, followed by Obama, before a reenactment of the events of 70 years ago.