* Thousands of residents have been forced to leave their homes in Buller, Tasman and Marlborough districts
* States of Emergency declared in Marlborough and Buller; flood levels in Buller highest since 1926
* Two injured after tree falls on their car in Rangitikei district; multiple rescues of motorists trapped by floodwaters, including a heli-rescue of one from campervan roof
* Wild weather moving north, flooding closes highways at the top of the South Island and in Wellington, ferry services cancelled in Auckland
Thousands of people have spent the night in makeshift accommodation with entire towns evacuated at the top of the South Island after some of the worst flooding in nearly a century.
Evacuations continued overnight in parts of the upper South Island - with the township of Tuamarina in Marlborough the latest - while flooding and slips were also causing traffic headaches for Wellingtonians as the foul weather moved north.
Two people have been hurt - one seriously, one moderately - after a tree fell on their car in Hunterville, north of Palmerston North, about 4pm. Both are in hospital.
Major highways at the top of the South Island are closed, including parts of SH1, SH6 and SH7.
In Wellington, State Highway 2 was closed to northbound traffic between Ngauranga interchange and Dowse interchange, due to flooding, Waka Kotahi NZTA Wellington tweeted.
The SH1 Johnsonville southbound off-ramp and SH2 Remutaka Hill were also closed. SH1 Johnsonville to Tawa and SH1 Paremata had lanes blocked.
The Riverbank carpark in Lower Hutt was also flooding and was, as of 5.40pm being closed by Hutt City Council.
"Around 20 vehicles are parked in the carpark and the owners are being asked to urgently remove them due to concerns that flood levels will further rise.
"Owners who cannot get to the carpark to move their vehicle may have their vehicle moved to higher ground."
All of Tuamarina township - 270 people in 99 properties - near Blenheim have been told to evacuate due to a breached stop bank.
Earlier the nearby entire Spring Creek township - 430 people across 162 properties - were told by Marlborough District Council to evacuate, with an "overtopping stop bank" on the Wairau River threatening properties.
Mandatory evactuations earlier occurred in other parts of Marlborough and again in Westport, following a mass evacuation in the Buller District on Friday night.
Marlborough evacuees should stay with friends or family in the Blenheim area, a Marlborough District Council spokesman said.
"If you have nowhere to go, please call the Council on (03) 520 7400 or go to Stadium 2000 in Kinross St, Blenheim where an information centre is being set up.
"Evacuees will be allowed to cross the Wairau River bridge on SH1."
Earlier pn Saturday afternoon, residents of two Westport streets were told to leave their homes.
Houses from No 99 to 158 in Brougham St and all of Eastons Rd need to evacuate, the National Emergency Management Agency tweeted at 3.42pm.
More than 820 people have already been forced from their homes in the Buller District, where Westport is located, after flooding began on Friday night.
More information go to https://bullerdc.govt.nz or the Buller Emergency Management Facebook page.
Authorities also told Lower Wairau, Marlborough, residents to evacuate, with the Wairau River running "very high" of the State Highway 1 bridge.
"The bridge ... has just been closed. The river is running very high, just under the structure," a council spokesman said.
"Residents in part of the Lower Wairau have been advised to evacuate due to a stop bank breach near Ferry Rd bridge."
An evacuation centre had been set up at the Rarangi Fire Station, he said.
The affected area is Neal Rd bridge to Chaytors, Connollys and Wairau Bar roads.
The only access point now is via Neal Rd bridge, into Rarangi Rd. Police have also closed SH1 just north of Picton, and at Spring Creek.
Due to slips and flooding, SH2 is also closed between Upper Hutt and Featherston, Waka Kotahi NZTA tweeted.
Eight motorists were earlier rescued from their cars after being trapped by floodwaters as wild weather batters the South Island - and causes disruptions in Auckland and Wellington.
A front-loader and a helicopter were called to rescue people stranded on the roofs of their vehicles, a Fire and Emergency spokewoman said.
On SH1 at Tuamarina, north of Blenheim, five people from two vehicles were rescued after they were caught in floodwaters.
"SH1 is closed between Picton and Spring Creek, with no detour available. Motorists are reminded to respect road closures and not to attempt to drive through floodwater", the spokeswoman said.
A state of emergency was declared in Marlborough by deputy mayor Nadine Taylor at 12.20pm.
The Marlborough District Council has advised residents of the Lower Terrace in Renwick to evacuate their properties and stay with family or friends for the next 24 hours, as the stop bank at Conders Bend was beginning to overtop.
Taylor said the declaration would ensure the emergency response team had the resources needed to conduct evacuations, which affected 221 properties in Alma St North, Gee St, Blicks Rd, Brook St North, Inkerman St North, Oudenarde St and Terrace Rd.
An information centre had been set up at Renwick Hall, 27 High St, by Marlborough Emergency Management.
Meanwhile, Bartlett's Creek bridge, 20km up Northbank Rd from Renwick, has been washed out so access to the Northbank area west of SH6 is now not possible. About 25 rural properties there are cut off.
Westport and Nelson have been left isolated as high river levels, flooding, fallen trees and slips close state highways across the top of the South Island, RNZ reports.
Niwa's hydrodynamics scientist, Richard Measures, said flood levels at the Buller Te Kuha monitoring station are now the "highest since the major flood of 1926".
In Nelson, the local Civil Defence management group said several roads have been closed to keep people safe, power is out in two areas, but the heaviest rainfall has passed.
The rare "red warning" urging West Coast residents to brace for wild weather has been extended for an additional seven hours as the region deals with flooding, slips, mass evacuations and major road closures.
The wild weather also caused disruptions in the North Island - cancelling ferry services in Auckland and disrupting 28 domestic flights and blowing roofs off homes in Wellington.
The 11am and 12 noon ferry services from Auckland to Waiheke Island were cancelled as a result of bad weather conditions, said Fullers.
Heavy winds also battered Taranaki on Saturday. On the Extreme Weather Taranaki Facebook page, peoplereported shaking windows, a porch being blown out and waves crashing over a rock wall at Port Taranaki.
"When is this wild weather due to go away? Feels like my house is going to blow away," said one woman.
Wellington City Council had by midday received "more than 20 calls to reports of flooding on roads and into private properties since 8am today – and the rain is continuing to fall heavily".
Crews had been working to clear away a toppled tree in Oban St, Wadestown and there had been multiple reports of flooding across the city – including into shops in Adelaide Rd, Berhampore, the council says.
Greater Wellington Regional Council is urging dog owners to keep their dogs away from the Hutt River and Wellington Harbour beaches until staff have checked these areas for dead possums poisoned with 1080.
Heavy rain may have washed dead possums poisoned with 1080, from a possum control operation on July 2 in the Akatarawa Forest, down the Hutt River and into Wellington Harbour, the council said.
Greater Wellington biosecurity manager Davor Bejakovich said any dead possums that had washed ashore would not be a threat to people, but would still be poisonous to dogs.
The MetService-issued red warning - only the third to be declared - for Buller and Westland is now due to end in Buller on Sunday at 3am.
More than 820 people were evacuated from 374 houses in Buller on Friday night. Some residents in the Tasman District had also been forced from their homes.
The weather bomb that hit the South Island's West Coast this weekend - described as a one-in-50-year storm - has closed all roads into the Buller and prompted regional emergency management to declare a state of emergency.
Wild weather moved up the country on Saturday - bringing periods of heavy rain to many parts.
The country's weather authority issued a spate of weather warnings for the country, including a North Island-wide strong wind warning.
Buller mayor Jamie Cleine said 823 people were evacuated over four hours on Friday night, and 500 of them spent the night in community welfare centres across Westport while others stayed with friends and family.
The Buller River had swollen to an "extremely high" 12 metres with more rainfall from the ranges to come, he said.
"[It's] at least a 50-year flood event," he said.
There were nerves around the 3.30am high tide with a tidal surge predicted - but both had passed without significant impact, Cleine said.
SH6 from Westport to Rapahoe and SH73 from Arthurs Pass to Jacksons were both closed due to slips.
SH7 from Ikamatua to Stillwater is closed due to flooding, while flooding and multiple slips have closed SH65 from O'Sullivans Bridge to Shenandoah, and SH60 from Collingwood to Riwaka.
Greymouth resident Barry Gray's Peel St home was surrounded by floodwater.
Unable to leave, he got McDonald's delivered to his home.
"I couldn't get out to get a feed, it's pretty bad here," he told NZ Herald journalist George Heard.
"We've only been living here the last few months, and the lady said it gets quite bad. You've got to watch out for when it rains hard-out. I didn't think it was going to be this bad."
He said as the heavy rain set in last night, he was worried it would burst through his windows.
"Quite lucky it hasn't actually come up through the floorboards yet," he said.
"I'm quite worried. It's getting quite high now."
Tasman District Council spokesman Chris Choat said staff were knocking on doors at 3 or 4am asking people to leave their homes.
He said a small number of houses at Brooklyn, near the Riwaka River, were evacuated as a precaution.
A Fire and Emergency NZ spokesperson said one person was rescued from the roof of their car in the Tapawera River.
"Crews from Tapawera and Motueka attended but were unable to get near enough to the vehicle to reach the motorist because of flooding."
A front-loader was used to retrieve a motorist trapped on the roof of their car by floodwater on Kawatiri-Murchison Rd.
And Fire and Emergency NZ crew were called to rescue a motorist who had become stuck in floodwater off Rogerson Track, near Hanmer Springs.
In Wellington, Fire and Emergency had 28 weather-related calls overnight and responded to 19.
Shift manager Belinda Beets said many of them involved roofs being blown off.
A large section of a roof came off a house in Newtown. Roofing iron and a sign also came loose elsewhere in that suburb.
Steel was hanging from a roof on an apartment block on Taranaki St in the CBD, and doors were blown out in Ngaio.
More than 700 people in Buller were evacuated from low-lying areas to four evacuation centres in the district.
Evacuated residents were this morning asked to "stay away" from their homes, as the risk of moving floodwaters remained.
West Coast Emergency Management this morning said there was still a large amount of water in the ranges that needed to make its way down the Buller River.
"We know you are keen to get home. We ask people to stay away from their homes while the risk remains. We will let you know when it is safe to return home."
Last night the Army deployed 14 personnel and seven vehicles from Burnham Military Camp in Canterbury to assist with evacuations following flooding.
When Cleine visited the centres this morning, people were sitting around playing cards, waiting for more information on the situation.
"We're just reinforcing that message that even though we're really happy with how things are going, we just need another couple of hours to make sure the river has settled down."
In Westport, Fire and Emergency received 12 calls about trees that had blown down.
Shift manager Lyn Crosson said fire crews didn't attend some of those because the council attended instead.
MetService meteorologist Rob Kerr said bad weather would move up the country today swiftly - bringing periods of heavy rain to much of the North Island.
"Bang, it's going to accelerate right across [the North Island]. It will be quite brief moving through," he said.
In Auckland, Fullers has halted some of its Waiheke Island services due to bad weather.
The 11am and 12 noon Auckland to Waiheke services and the Waiheke to Auckland noon and 1pm services were cancelled.
Strong northerlies will rattle the City of Sails today with gales gusting 100km/h in exposed places, turning northwest and easing by the evening.
Weather warnings across the country
MetService has issued a strong wind watch from the Far North to the capital city - in effect until 8pm tonight.
North Islanders were being warned that wind strengths could approach severe gale in exposed places.
Up to 200mm of rain could accumulate about Mt Taranaki and up to 120mm about the Tongariro National Park.
Taihape and inland Whanganui are in for a windy Saturday, with north to northwest winds expected to be severe in exposed places, with gusts of up to 120km/h.
It is a similar story on the other side of the North Island, with a heavy rain warning in place from 1pm to 10pm on the Bay of Plenty, east of Whakatāne and the ranges of Gisborne.
Heavy rain warnings are also in place for the Tararua Ranges until 6pm in Wellington and until 3pm in Marlborough.