World leaders have expressed sympathy and sorrow at the Duke of Edinburgh's death.

In a statement, Prime Minister Jacinda Ardern expressed condolences to the Queen and the Royal Family.

"Our thoughts are with Her Majesty The Queen at this profoundly sad time. On behalf of the New Zealand people and the Government, I would like to express my sincere condolences to Her Majesty and to all the Royal Family," Ardern said.

"Prince Philip will be fondly remembered for the encouragement he gave to so many young New Zealanders through The Duke of Edinburgh's Hillary Award. In over 50 years of The Award in New Zealand, thousands of young people have completed life-changing challenges through the programme.

"New Zealanders will also remember The Duke of Edinburgh's enormous support for Her Majesty The Queen. His time as royal consort exceeded that of any other royal consort in British history. His Royal Highness accompanied The Queen on her 10 visits to New Zealand, the first being in 1953, and the last in 2002."

Ardern said that she had directed that flags on all Government buildings and naval vessels be flown at half-mast.

National Party leader Judith Collins offered condolences tweeting the news was "so sad for Her Majesty, the United Kingdom, and the Commonwealth."

In the UK, Prime Minister Boris Johnson said it was "with great sadness" that he received news of Prince Philip's death from Buckingham Palace.

Paying tribute, he said the Duke of Edinburgh earned the affection of generations in the UK, across the Commonwealth and around the world.

"He was the longest serving consort in history, one of the last surviving people in this country to have served in the Second World War where he was mentioned in dispatches for bravery."

Scotland's First Minister Nicola Sturgeon said she was "saddened" by the death of the Duke.

She tweeted: "I send my personal and deepest condolences - and those of scotgov and the people of Scotland - to Her Majesty The Queen and her family."

Australia's Prime Minister Scott Morrison released a statement saying, for nearly 80 years, Prince Philip served his Crown, his country and the Commonwealth.

"His Royal Highness The Duke of Edinburgh was, in the words of Her Majesty, her 'strength and stay'.

"He embodied a generation that we will never see again."

US President Joe Biden also sent condolences, praising the duke for his dedication "to the people of the UK, the Commonwealth and to his family", as well as for his service during World War Two, championing environmental efforts and inspiring young people.

Canada's PM Justin Trudeau was among other Commonwealth leaders to pay tribute saying the duke had "contributed so much to the social fabric of our country - and the world".

He added: "Prince Philip was a man of great purpose and conviction, who was motivated by a sense of duty to others. We will fondly remember him as a pillar in the life of our Queen."

Pakistan's PM Imran Khan said Philip had been a "wise leader" and his "role in promoting Pakistan-UK relations will always be remembered".

And Indian Prime Minister Narendra Modi was another to praise a lifetime of dedication to "many community service initiatives".

Kenya's President Uhuru Kenyatta said the duke was a "towering symbol of family values and the unity of the British people as well as the entire global community" - a man who had worked for the "peaceful co-existence of the human race".

Other warm condolences from Africa included Zimbabwe - which has had a rocky relationship with the UK and is no longer in the Commonwealth - and the president of Tanzania, which only recently lost its leader John Pombe Magufuli amid Covid-19 rumours.

'Cherish the memories'

Prince Philip had blood ties with a number of former or current European royal households, and many of their members have been sending condolences.

The telegram from King Felipe and Queen Letizia of Spain was particularly poignant, sending "all our love and affection" to Aunt Lilibet (the affectionate name used by the duke for his wife) and Dear Uncle Philip.

"We shall never forget the moments that we shared with him and the legacy of service and dedication to the Crown and the United Kingdom by your side," they told the Queen.

Sweden's King Carl Gustaf was also moved, saying the duke had been "a great friend of our family for many years, a relation we have deeply valued".

Swedish royal family spokeswoman Margareta Thorgren told the BBC the king and the duke had sailed together in England, adding: "That was the start of a great friendship between them."

The Dutch royal family said they remembered Prince Philip with great respect, adding: "He dedicated his long life to the service of the British people and to his many duties and responsibilities. His lively personality made an indelible impression."

Belgium's King Philippe said he and Queen Mathilde would "always cherish the memories of our warm encounters".

'Long and remarkable life'

Other tributes came from nations deeply linked to the duke and his family.

Malta's Prime Minister Robert Abela wrote: "Truly saddened by the loss of Prince Philip, who made Malta his home and returned here so often. Our people will always treasure his memory."

Philip and Elizabeth spent two idyllic years on Malta, where he was stationed in the Navy, before King George VI died in 1952.

Israel's PM Benjamin Netanyahu said the duke was "the consummate public servant and will be much missed in Israel and across the world".

The duke's mother, Princess Alice of Battenberg, who died in 1969, is buried at the Church of Mary Magdalene in Jerusalem.

In a personal tribute, Barack Obama, one of the 18 US presidents in the duke's lifetime, said Philip had immediately put him and Michelle at ease, and that he was "kind and warm, with a sharp wit and unfailing good humour... we will miss him dearly".

Donald Trump said Prince Philip "defined British dignity and grace. He personified the quiet reserve, stern fortitude and unbending integrity of the United Kingdom... He will be greatly missed".

In a telegram to the Queen, Russian President Vladimir Putin said the duke had "rightfully enjoyed respect" both at home and internationally.

And Chancellor Angela Merkel said the duke's "friendship with Germany, his straightforward nature and his sense of duty will remain unforgotten".

France's Foreign Minister Jean-Yves Le Drian summed up many of the tributes - calling the duke a man of "great style".

"France joins in the sorrow of its friends across the Channel and salutes the life, at once European and British, of a man who was a witness to a century of trials and hopes for our continent."

President Emmanuel Macron said the duke had led an "exemplary life".

- ABC, BBC