"Catherine and I are thinking about all those affected. W"
A local state of emergency remains in place in Marlborough, as the bad weather continues to batter the region this morning.
In Nelson, more than 500 homes have been evacuated over the last couple of days, with Civil Defence saying that number looks set to increase even more.
Even more people have self-evacuated, with a red rain warning in force again in place for Nelson until 10am.
Marlborough District Mayor John Leggett said their roading network remains a massive challenge.
Motorists in the Nelson-Tasman region are being advised to limit their travel to essential travel only.
READ MORE: 'Unbelievable' wild weather - further flooding as heavy rain hits again overnight
The duke is known to have a "very close relationship" with New Zealand and sat down with Prime Minister Jacinda Ardern last month at Kensington Palace.
While details of private meetings with members of the royal family are usually kept strictly secret, Ardern said it was a good opportunity to "meet and reconnect" with the heir to the throne.
She told the Herald, "Prince William is someone who has a very close relationship with New Zealand," adding that they spoke about the Earthshot Prize, one of William's environmental projects.
She also noted that "the love and affinity that Prince William has for New Zealand is very, very strong".
Following the heartfelt tweet, many royal fans were quick to send their love to New Zealand in the wake of the devastating floods.
One person said, "Thinking about the people of New Zealand," another said, "Thinking of the people of this wonderful country".
Another adding, "Climate change is real and it will continue to affect the entire world if nothing is done. Stay strong Kiwis".
While a fourth retweeted, "A kind and thoughtful message".
It comes after days of intense rain caused widespread damage across Marlborough, Buller and Nelson Tasman, displacing hundreds of people, while closing roads and disrupting lives in other parts of the country.
Forecaster for the national weather authority Gerard Bellam said an atmospheric river had been "parked up" over the country as a "very large, intense" front sat to the east of New Zealand, preventing the weather system from moving away, and bringing prolonged rain.
However, that weather system was expected to move off the country this afternoon, meaning some reprieve in Nelson, as well as other parts of the country that have been doused this week, including Marlborough, Taranaki and Northland.