Roads closed by extensive flooding and slips in the lower North Island are reopening tonight, but transport authorities are warning motorists to continue to take care.
Whanganui was cut off from surrounding regions after the wild weather closed State Highway 3 both north and south of the city.
However, Mark Owen of the New Zealand Transport Agency said the highway had been reopened between Bulls and Whanganui this evening, restoring southern access to the city.
"The Whangaehu River Bridge has been reopened and is operating under stop-go control and speed restrictions. Please take extreme care and avoid non-essential travel," Mr Owen said.
Earlier, northern access to Whanganui was restored when SH3 between the city and New Plymouth was reopened. However, Mr Owen warned the road's condition was "poor" and he advised against non-essential travel.
Also reopened tonight was SH1 near Marton, which meant the country's main highway was "now fully open".
Speed restrictions were in place on SH1 at Marton and the Waikawa River Bridge, and motorists were urged to take care.
"Just because a highway is open doesn't mean it is clear sailing," Mr Owen said.
"Debris, slips, surface flooding, one-lane restrictions and potholes are widespread, and it is essential people put safety first, drop their speeds and expect the unexpected.
"It is also essential to drop speeds to keep contractors safe while they are working on the roads. We recognise that many people are anxious to return home to loved ones, but if you must travel, allow plenty of extra time for your journey."
Mr Owen said crews were continuing to target the Manawatu Gorge.
"While there are no major slips, there are a number of smaller slips that require clearing and geotechnical assessments are required to ensure the stability and safety of the affected slopes.
"It is likely to be closed for a few days, with a further update expected tomorrow."
Mr Owen said the agency was continuing to monitor weather forecasts, as a cold blast was on its way.
"We are committed to ensuring as many route options are available in the event of snow-related closures. We will in particular be monitoring the Central Plateau and Rimutakas."
Residents of flood-stricken Waitotara are being offered alternative accommodation, clean drinking water supplies and portable toilets after the township was hit hard by the downpours that lashed the lower North Island yesterday.
A state of emergency is still in place in Taranaki because of the Waitotara flooding.
Residents were evacuated from the township between 9pm and 10pm yesterday.
Taranaki Civil Defence Emergency Management Group reminded people to take care on the roads when driving.
Locals were also advised to stay away from beaches, rivers and streams until Tuesday because of potential contamination as a result of the heavy rain and flooding.
Director of Civil Defence Emergency Management, Sarah Stuart-Black, said although the rain had eased, some rivers were only expected to start receding by early afternoon today.
"We remain in contact with Civil Defence Emergency Management groups throughout the event.
"People are advised to watch council websites for detailed updates on the situation, as well as the New Zealand Transport Agency website for the latest information on the status of state highways."
Civil Defence Minister Nikki Kaye said states of local emergency were declared to enable people to be evacuated to safety.
"The flooding in areas such as Waitotara and Wanganui has been very severe.
"In situations like this, it's important that local Civil Defence Emergency Management teams can take actions necessary to help evacuate people and save lives.
"It was a long night for many, and as inspections are carried out today where possible, we'll get a better assessment of the impact of this severe storm."
Ms Kaye said responding agencies were working hard to ensure people were safe and had accommodation and other assistance.
She said most of the focus would now turn to clean-up and recovery.
"I have been in regular contact with local mayors, and the National Crisis Management Centre in Wellington has been activated to ensure local authorities have the support they need.
Ms Kaye said the government would help local authorities with the costs of response and recovery.
"We will also work alongside councils to provide further support where necessary."
Damage could be in "the millions"
This afternoon, an Insurance Council spokeswoman said damage from the event "could run into the millions".
Insurance Council chief executive Tim Grafton said it would be some time before the extent of the insured damage was known.
"The priority now is for insurers to get assessors out to communities and get the claims process underway."
Mr Grafton reminded people to contact their insurance provider as soon as possible and take photographic evidence of flooding and damage to their homes, to help with their claims assessment.
Whanganui remained cut off this morning after the biggest flood on record swept through the city overnight.
More than 100 households were evacuated yesterday, mostly on the eastern banks of the Whanganui River, and hundreds more self-evacuated.
The Whanganui River breached its banks around midnight, spilling floodwaters into Whanganui's CBD, and the flood has been called a one in 85 year event.
Gene Toyne, her husband Chris, and their two dogs, who live in a low-lying area near Whanganui Airport, left their house yesterday afternoon.
Mrs Toyne said they woke early yesterday morning to find flood waters lapping around their house. They spent the morning moving their livestock and valuables to safe areas.
"We sat down for a cup of coffee around 1.30pm, because we hadn't stopped all day, and in less than half an hour the water was coming through the floor."
This morning, Whanganui 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 from 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."
Taranaki
Around seven or eight residents of the Waitotara township in South Taranaki were evacuated last night as rising river levels threatened their safety and their homes.
George Kent, who owns the Clarendon Hotel in Waverley, near Waitotara, said the hotel offered beds to residents who were evacuated from the township last night.
This morning, group controller for the South Taranaki District Council, David Lean, said staff were assessing a number of flooded houses in Waitotara.
A helicopter had flown into the Waitotara Valley this morning, to assess conditions and respond to two requests for assistance.
This afternoon, a Taranaki Civil Defence controller would take a Taranaki district council member on a helicopter inspection of Waitotara Valley.
They will also drop off emergency fuel supplies for a Waitotara Valley household.
Flooding and fallen lines cut power to about 170 properties in Waverley and Waitotara, while in Taranaki, three areas had supply cuts. Kim Lewis lives on the Whanganui side of the Waitotara River.
She said Fire Service crews visited her home at 11pm yesterday with an evacuation order, but she chose to stay at home to take care of her livestock and her dogs.
"There are seven houses I saw this morning that are seriously, seriously flooded with water inside the houses.
"They've been hit before. They are pretty gutted but they're country people and you just sort of pick up and carry on - everyone mucks in and gets in behind you, trousers pulled up, bare feet.
"They're trying to lift up as much as they can."
Ms Lewis said the rain had stopped, and the water was already beginning to recede quickly.
Meanwhile, there were many disruptions to the highway network in the region.
SH3 north was now open after earlier being blocked by a slip near Uruti, and SH3 south from Hawera to Whanganui has reopened but was down to one lane in many places.
Civil Defence Emergency Management advised people to take care when driving today due to slips and flooding on local roads.
People were also advised to stay away from beaches, rivers and streams until Tuesday because of potential contamination as a result of heavy rain and flooding.
Rangitikei
In Rangitikei, around seven or eight people were evacuated from their homes in the isolated coastal village of Koitiata, with help from the army.
In the Koitiata area there was no cellphone coverage and landlines were only working intermittently.
Rangitikei Mayor Andy Watson said he expected more evacuations in the region by the end of today as people headed back to their houses and realised "their home is a mess".
"It wouldn't surprise me if we were dealing with 20 or 30 more [evacuations]."
Mr Watson said a helicopter flyover with Civil Defence late this morning revealed much of the coast near Turakina beach was blocked off from SH3 by flooding.
"We do not have access other than by air to Turakina beach so we have got to find some kind of way to get rid of massive amounts of water."
Mr Watson guessed there were "a hundred-odd people" at the beach who were currently unable to leave.
Meanwhile, a number of people in Whangaehu had been isolated by floodwaters and it was too dangerous to retrieve them, even by helicopter, Mr Watson said.
"That was six to 10 people - they were fine but we have to wait for floodwaters to recede before we're in a safe position to get them out."
Locals were being evacuated to the nearby town of Marton, where they were being housed "anywhere they could".
However some Marton accommodation was now flooded as well.
Civil Defence Emergency Management said water contamination was expected due to power loss to sewage pumps, and people across the region were advised to save water and limit flushing of toilets to avoid contamination.
In Palmerston North there were some slips and surface flooding around the area.
In Levin and Foxton a number of people were evacuated from their homes overnight.
As more rain was expected between 6pm and midnight in the Horowhenua region tonight, Civil Defence Emergency Management said the situation would be closely monitored.
- NZME. with additional reporting from the Wanganui Chronicle