Torrential rain has devastated parts of the South Island for the fourth day in a row, forcing hundreds from their homes as rivers overflow.
Nelson, on the north coast of the South Island, was the worst affected, with more than 400 homes evacuated and some declared uninhabitable because of the rains.
The Duke of Cambridge responded to the crisis by offering his heartfelt support to those affected, and called for a “herculean effort” to “protect the planet”.
The Prince tweeted: “Seeing the devastation caused by the floods in New Zealand is a reminder of the herculean effort we must all make to protect our planet.
“I know you will come together, as you have done before, to support those in need.
“Catherine and I are thinking about all those affected.”
Twitter user @loveforcambridg responded: “Climate change is real and it will continue to affect the entire world if nothing is done.
“Stay strong Kiwis”.
Another replied: “A kind and thoughtful message”.
Alec Louverdis, group controller for Nelson Tasman Civil Defence, told a news conference: “The damage I saw in Nelson was heartbreaking and I think we are years away from a recovery.”
He added: “As we were driving there were slips everywhere,” referring to landslides.
Weather forecaster Metservice said Nelson had had 172 mm (6.8 inches) of rain since Tuesday, which is more than double its average August rainfall.
Another 190 mm is expected to fall in the hills near Nelson over the next day.
Residents in affected areas are being told to save water due to problems with the city’s water system.
The latest rainstorms come after weeks of wet weather for the country.
Experts have said the unseasonably wet weather is due to a narrow stream of water vapour, or an “atmospheric river”, above the country.
Meanwhile heavy rains have hit New Zealand’s North Island over the past 24 hours.
Some towns have been cut off, roads and houses left under water and people being evacuated.
Civil Defence Northland said in a Facebook post that some flooding was expected to ease as the tide falls today – but some roads remain cut off.
A heavy rain warning remains in place until midnight on Friday.