Floodwaters that have inundated Edgecumbe are contaminated with sewage, while more evacuations are possible.
The Bay of Plenty town remains cordoned off, after the Rangitāiki River breached a stopbank yesterday, forcing the evacuation of the entire Bay of Plenty town of 1600 people.
With floodwaters still moving down rivers and canals, people in low-lying areas north-west of Edgecumbe could still have to leave their homes.
The water levels had stabilised, and authorities hope they can begin pumping out floodwaters tomorrow morning.
Work has started to repair the stopbank breach. Once that was complete, floodwater could be pumped from the town - a process that could take two weeks.
Whakatāne Mayor Tony Bonne said the sewerage system was not working, so surface water was likely to be contaminated - and people in the entire Ruatoki and Rangitāiki Plains must boil all their water for at least one minute to make it safe to drink.
The Bay of Plenty Regional Council hoped to finish work on the stopbank tonight. Once that happened, they could start pumping floodwater from the town - a process that could take two weeks.
The Ministry of Health must give clearance before residents return to Edgecumbe because of likely sewage contamination.
Communities still cut off
Mr Bonne said people were still isolated in Minginui, Ruatahuna, Te Whaiti and Ruatoki.
He said they were trying to figure out exactly how many people were cut off and emergency supplies were being delivered by air.
More properties across 500 hectares in the Bay of Plenty could be evacuated as flood waters moved to lower ground.
Council flood manager Roger Waugh said properties to the north-west of Edgecumbe, towards the Awaiti Canal and up near Thornton and Matata Roads, were most at risk.
"The floodwaters are migrating down to the lower areas and down into the lower canals. There are issues as it goes through there, there's likely to be maybe some other evacuations, there'll be other property affected and of course obviously it's a farming community, so there's obviously stock and the dairy operation that's being affected."
Mr Waugh said the water may not reach those areas, but residents should stay on high alert.
Significant insurance claims expected
The Insurance Council said it expected claims from this week's floods would be significant. Edgecumbe was badly hit by floods in 1998 and 2004.
Its executive director, Tim Grafton, said he did not believe insurance companies would walk away from Edgecumbe.
"It looks like fairly substantial damage will have been incurred, so you know this is certainly going to be in the multi-millions of dollars, even for Edgecumbe."
Help for Edgecumbe residents
The Ministry of Education said with the cordon still in place, Edgecumbe School and Edgecumbe College were unlikely to be assessed until Monday at the earliest. The schools were not expected to have been badly damaged because they are on higher ground.
The ministry said 29 schools and 38 early learning services across the wider North Island were closed today because of the severe wet weather, affecting 3101 students and 1252 pre-schoolers.
Local people dropped donations off to those evacuated from Edgecumbe.
Amont them was Lenora, who lives in Poroporo and was evacuated yesterday.
She said she had a lot of family around to stay with - so wanted to drop something off for people at the Whakatāne evacuation centre.
"The support was there for me, so this morning when we woke up and saw all the families that have lost a lot, so we just wanted to help, come and drop off some kai."
Prime Minister Bill English visited Edgecumbe today. He said some residents would never be able to go back to their homes. He said an investigation would be needed to determine how the breach in the Rangitāiki River's stopbank occurred.
Fonterra still closed
Fonterra did not to reopen its factory in flood-decimated Edgecumbe today as it had hoped.
It said new information about the state of the nearby floodbank delayed the re-start. It would continue to assess the situation.
Fonterra said flooding affected about 50 of its local farms.
The co-op said it received a huge number of calls from nearby farmers with offers of help managing stock and support for the community.
It said where it could collect milk off farms, it was being redirected to manufacturing sites in the Waikato.
Thames-Coast road remains closed
State Highway 25, known as the Thames-Coast Road, was likely to remain closed between Tapu and Waiomu for several days after a large slip came down last night.
The slip of over 1000 cubic metres was at Ruamahanga.
The Transport Agency said a helicopter was sluicing the slip. Diggers were likely to be brought in tomorrow to begin clearing away mud, rock and debris.
A food and wine festival at Matarangi would go ahead tomorrow.
The Transport Agency said those travelling to the event should use the State Highway 25A route, through Kopu and Hikuai, and allow extra travelling time and expect some delays.