The Royal Family Twitter account confirmed the news on Friday night. The 99-year-old prince had recently been hospitalised in February 2021 for what Buckingham Palace said was a "precautionary measure" after he felt ill.
Ardern says flags on all government buildings and naval vessels will be flown at half-mast and following his funeral a national memorial service will be held in Wellington.
During his lifetime Prince Philip visited New Zealand 15 times - 10 with the Queen, and five without her.
In 1953 he was at the side of the newly crowned Queen as the couple visited 46 towns and attended 110 functions.
"New Zealanders will also remember The Duke of Edinburgh's enormous support for Her Majesty The Queen," Ardern says.