Prince William will attend the New Zealand Commemoration for the Battle of Passchendaele on October 12, Kensington Palace has confirmed.
Prime Minister Bill English this morning welcomed the announcement.
The commemorations will take place at Tyne Cot Cemetery, near Zonnebeke in Belgium - the largest Commonwealth War Grave cemetery in the world.
"The Duke of Cambridge, representing HM The Queen, will attend the New Zealand Commemoration for the Battle of Passchendaele on 12th October," the Palace tweeted.
The cemetery contains 520 New Zealand graves and more Kiwi soldiers are listed on the New Zealand Memorial to the Missing in the Battles of Passchendaele.
The Prince will be joined by Princess Astrid of Belgium, who will attend on behalf of her brother, King Philippe.
"It is fitting that the Duke of Cambridge will be there to mark 100 years since the battle and to recognise an important part of New Zealand's story," English said.
"Passchendaele was the greatest disaster in New Zealand military history. Some 843 men are recorded as having lost their lives on 12 October 1917, the most on any single day of combat involving New Zealand troops.
"A century later we will remember the courage and sacrifice of those who fought and died and commemorate a significant chapter in our nation's history."
English said the attendance of Princess Astrid would provide an opportunity for Belgium and New Zealand to remember the events which "so profoundly affected" both countries.
The Government will be represented at Tyne Cot by Cabinet minister Nick Smith, and Speaker of the House David Carter will represent Parliament.
In Wellington, commemorations will begin at 3pm on October 12 at the Pukeahu National War Memorial Park.
A memorial gifted to New Zealand by the Belgian Government will be unveiled on the eastern terraces of the park following the ceremony.
Arts Culture and Heritage Minister Maggie Barry described Passchendaele as "one of the greatest disasters in New Zealand history".
"This devastating loss of life remains the highest one-day death toll suffered by New Zealand forces overseas," Barry said.
"During the Third Battle of Ypres, which included Passchendaele, New Zealand lost nearly 2000 men. We will remember them and all who fought in Belgium."
Ceremonies will conclude at sunset at Buttes New British Cemetery in Polygon Wood where 95 Kiwis are buried.
It is also where the New Zealand "Memorial to the Missing" list the names of the 388 Kiwis who died there, but did not have a grave.