MetService is forecasting more severe rain on the South Island's West Coast - which could cause dangerous river conditions and flooding in Buller.
The area is now seeing a brief reprieve from the rain, but meteorologist Lewis Ferris said significant rainfall is expected in parts of Buller and Westland again this afternoon, continuing into tomorrow.
Civil Defence said there have not been any significant problems because of the heavy rain in Westland over the past 24 hours.
Emergency workers say they had reports of the Makaawhio River breaching its banks, but that was not cause for serious concern. They hope the district's red weather warning will be downgraded.
Buller Emergency Operations Centre controller Bob Dickson was asking anyone who could safely leave their home and stay with family or friends outside of Westport, to do so.
"I know leaving your homes behind is very disruptive and distressing, but the community now has time to move safely before more rain sets in," Dickson said.
"For those residents who cannot easily self-evacuate to stay with family or friends, they should prepare for possible evacuations in coming days."
Dickson said it was still safe to travel out of town via the Coast Road and the Buller Gorge, but locals should avoid heading north, where heavier rain is expected to fall.
Evacuation centres have been stood up at the Greymouth Baptist Church, on 76 High Street, at Sergeants Hill and at the Waimangaroa Community Hall.
Dickson said anyone whose home was flooded last July should evacuate as a precaution.
Buller Emergency Management is reminding people to have medications, food, water, blankets and warm clothes in a bag ready to go.
It also said to have a plan for pets, and make sure vehicles are ready to take them to higher ground if need be.
A Defence Force spokesperson said four trucks, one support vehicle and 10 personnel were in Greymouth, ready to help with evacuations.An air force helicopter is also in Hokitika.
The spokesperson said more resources were on standby and would be sent to the West Coast if needed.
Closures, slips, and power cuts
At Haast, 244mm of rain has fallen in a 24-hour period. About 100mm fell in the six hours from 6pm Wednesday.
There had been warnings of more than one metre of rain in the 48 hours to tomorrow morning. MetService meteorologist Ferris said it eased slightly overnight but is expected to get heavier again.
State Highway 6 between Franz Josef and Haast on the West Coast will remain closed for the day because of slips and flooding.
A slip has also closed State Highway 6 between Franz Josef and Fox Glacier.
Road workers are trying to clear the debris north of Haast township and between the glacier towns, but progress will depend on the weather.
Mount Aspiring Road in the national park and the road to Kinloch near Queenstown are also closed.
People are being urged not to try to cross Dart River floodwater on foot or in cars.
Moira Whinham, who is the maintenance contract manager for Waka Kotahi on the West Coast, told Morning Report that aside from SH6 it seems that there were only a few minor slips and surface flooding in the Buller area overnight.
She said Waka Kotahi teams will continue to monitor the roads throughout the day and motorists should check the road conditions before heading out.
About 250 homes and businesses are without power in Fox Glacier on the West Coast because of the bad weather.
Westpower said the blackout is likely to have been caused by a slip that has washed out a pole.
The company says some roads around Fox Glacier are impassable because of slips. Phones are also down in South Westland.
South Westland Area School and Haast School will be shut today and tomorrow due to the flooding.
The Waiho River in Franz Josef was being closely monitored and several families living on the south bank of the river had been given the option to relocate to the Franz Josef township for the night, West Coast Emergency Management said. The Haast and Hokitika Rivers are also being monitored.
To the north, a state of emergency is in place in Buller district, where emergency management controller Sean Judd said significant rain was still to come.
Concern over Buller River with more rain likely
MetService forecasts continuing rain for Westland, possibly easing during Thursday, but with more heavy falls on Friday. For Buller, further rain is likely overnight on Thursday, Friday and Saturday morning.
Civil Defence is worried that torrential rain will cause flooding as bad as the devastating flood in Westport last July.
Around 70 homes were left uninhabitable after that, and another nearly 400 damaged.
Civil Defence group controller on the West Coast Te Aroha Cook told Morning Report that a lot of planning is underway to deal with the effects of the forecast weather, particularly for the Buller district.
"The concern is that in terms of the Buller River that it might do what it did back in July's event, or potentially exceed, given the intensity of rainfall that's been forecast to occur."
The critical time is the 24 hours from late this afternoon through until tomorrow morning and also Saturday morning, she said.
Cook said they are encouraging those who are able to evacuate their houses, to do so now voluntarily.
She said a lot of homes were inundated in the July flooding on the West Coast.
"There are a lot of people that are still displaced from homes or have only just managed to get back into their homes.
"That has assisted with the planning in terms of the Buller Emergency Management Team because we do know where those pinch point areas were and that will be the priority for today in terms of too many people in those areas, and the need for them to potentially evacuate."
The district council has distributed more than 23,000 sandbags for people to protect their homes.
Buller District Mayor Jamie Cleine told Morning Report it is very likely some evacuations will be needed today.
"They'll be targeted, the team's done a lot of work overnight on finalising that plan of how we would stage it, but obviously the recent experience in July's informed the first areas that you would target and then based on the science and the engineering advice we get this morning would determine whether there's a larger extent or not."
Cleine said it is a very similar rain distribution forecast to that which happened in July.
He said it is "really devastating and anxious times" for those people who were hit by the flood in July and are now waiting to see whether there is a repeat over the next few days.
"The concern was never last night or today, we knew that that bit of rain would put a mild flood in the river but of no concern, it's fairly typical heavy rain for us - but what it's done is pre-charge the rivers and if we were to get the rain as forecast through Friday and Saturday then that would be problematic in Westport."
If needed, the primary evacuation location will be the industrial Holcim plant site which is just south of Westport and on high ground, Cleine said.
Buller Emergency Management has had reports of sandbags being removed from Chorus cabinets that contain fibre and copper network links and is asking people not to take those ones.
Sandbags have been put out elsewhere in both Hokitika and Westport for members of the public to use to protect their properties.
Sandbags are available from Pulse Energy Recreation Centre, and Kawatiri Coastal Trail Car Park by the Buller Bridge.
Chorus said it has been doing flood preparations to keep the telecommunications network going, including refuelling generators and putting sandbags and plastic wrap around cabinets in Westport.
Meanwhile, two trampers who were stuck overnight in a hut near Karangarua north of Haast on the West Coast have been rescued by helicopter and are safe and well.