Prime Minister Jacinda Ardern has expressed her "sincere condolences" to the Queen and 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.

"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".

Kiwis would also remember the Duke of Edinburgh's "enormous support" for 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 ten visits to New Zealand, the first being in 1953, and the last in 2002."

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

The Government was awaiting details from the palace concerning the arrangements for the Duke of Edinburgh's funeral, she said.

Following the funeral, a national memorial service will be held in Wellington. More details will follow once arrangements have been confirmed."

New Zealand Governor-General Dame Patsy Reddy said the Prince's death was a "great loss to Her Majesty the Queen, the members of the Royal Family and the people of Her Majesty's Realms and territories".

On behalf of the people of New Zealand, I convey our deepest condolences on the death of His Royal Highness Prince Philip. Our thoughts are with the members of the Royal Family at this time of great sorrow.

"New Zealand shares with the people of Her Majesty's Realms a tremendous sense of sadness at the great personal loss you have suffered," she said.

"We have fond memories of His Royal Highness's visits to New Zealand, and will remember his commitment to Commonwealth nations and his dedication to raise awareness of threats to the world's wildlife."

National Party leader Judith Collins paid tribute the Prince Philip's "truly impressive" charity work.

"His legacy will live on for many more decades to come."