A state of emergency that was declared in the Whanganui District last night remained in place this morning.
Around 200 people from around 100 properties had been evacuated from their homes overnight, the council said. A large number of residents had also self evacuated.
READ ALSO: Civil defence emergency declared in Wanganui
This morning Wanganui Mayor Annette Main said things were "dire", as the floodwaters in the area were higher than anyone had ever seen.
"Our bridge is closed, because there is such a huge volume of water flowing under, and obviously it comes from a big catchment so there are huge logs coming down and that is quite a danger.
"We've got a lot of people evacuated form their homes. They've been fantastic, being willing to be removed out in the dark, but it simply was necessary, the floodwaters are higher than we have seen them ever."
Ms Main said at this stage it was not expected that people would be able to return to their homes today.
"There's a lot of water around - a huge amount of water around."
Ms Main said she was cut off from her own home, as the area was evacuated due to the rising floodwaters.
"It's going to take some time for that [water] to recede. Concentration is on the areas around the river, where water has flooded over the stop banks.
"When water flows over the stop banks it can't get out easily again, so we are thinking about right now... what they may need to do to get some of that water back into the river.
"It's a bit of a balancing act at the moment. I think, in all seriousness, it's going to be tomorrow before people can get back to those homes."
A local state of emergency was also declared in Rangitikei, in Manawatu.Spokeswoman for the Rangitikei District Council Carol Downs said around seven or eight people were evacuated from their homes in the isolated village of Koitiata.
These people were evacuated with help from the army with unimogs, Ms Downs said.
"A lot of the people were actually able to go to higher ground so only a small number actually needed to be taken out of there."
There were around 140 homes in the small village, and those who had not been evacuated were now cut off from the highway, Ms Downs said.
"The community is cut off, not their homes." Ms Downs said the council was now trying to ascertain whether there had been any damage to homes in the area.
"There will be a helicopter going up shortly to have a look at damage right across the district, so we'll get a better picture after that."