It has been the most sombre moment of the royal tour so far, but one that matters just as much to Prince Harry.

The Duke of Sussex on Saturday officially opened the enhanced NSW Anzac Memorial in Sydney’s Hyde Park to honour the state’s fallen veterans.

The Centenary Extension finally realises the vision of the memorial’s architect Bruce Dellit, after it was first opened by Harry’s great-great uncle, the Prince Henry, Duke of Gloucester, in 1934.

Despite retiring from the British army, Harry has maintained his dedication to the military and honouring those who served throughout the Commonwealth.

And he has been particularly active in helping veterans – as attested to by his Invictus Games for wounded veterans which he will open later on Saturday.

Prince Harry wore the tropical dress of his regiment, the Blues and Royals, as he took part in the solemn ceremony alongside his wife Meghan, the governor of NSW, retired general David Hurley, Prime Minister Scott Morrison and NSW Premier Gladys Berejiklian.

General Hurley showed Harry and Meghan through the extension, which features a four-tier cascading waterfall which was part of the memorial’s original concept but was abandoned when the Depression hit and finances dried up.

They then entered into the new underground Hall of Service which houses a major artwork featuring 1701 soil samples taken from NSW towns and suburbs where young men and women enlisted for the First World War.

The couple, who announced earlier this week they were expecting their first child, continued their tour upstairs at the Hall of Memory.

The memorial extension, funded by the commonwealth and NSW governments, is the centrepiece of the state’s Centenary of Anzac commemorations to mark the 100th anniversary of the ending of the First World War this year.

The extension has been designed to enhance its role to support and provide services for veterans and their families, ensuring a public and a private place of contemplation, remembrance, education and reflection.
Harry and Meghan laid a colourful wreath of Australian native flowers at the memorial’s front step.

Harry saluted as the Last Post rang out across Hyde Park before the crowd of about 200 dignitaries and invited guests paused for a minute’s silence.

He then joined Ms Berejiklian on the steps to unveil a plaque for the memorial’s extension before three RAAF jets flew overhead.

The premier said it was poignant that the new $40 million extension had been completed just weeks before the centenary of the end of World War One next month.

She said the “majestic memorial” commemorated “all those who fought for our nation and made the ultimate sacrifice” and was a unique “place of reflection far from the horrors of war”.

Meghan wore a black, high-necked, full-skirted dress with buttons down the front by New Zealand-born, London-based designer Emilia Wickstead and a Philip Treacy hat.

-AAP