Over 700 people in Gore are being told to prepare to flee their homes as heavy rain continues to batter the South, adding to the 50 people already evacuated.
A carload of people had to be rescued from the top of their vehicle this afternoon and while some tourists were rescued by helicopter and boat today, others remain trapped overnight.
More heavy rain is expected tonight with a heavy rain warning in force for Westland, Southland, Otago excluding North Otago, and the headwaters of the Canterbury Lakes and Rivers.
State of emergency in Southland
A state of emergency has been declared in flooded Southland, including Gore.
It was issued by Southland Civil Defence Emergency Management Group shortly before 3pm.
About a metre of rain had fallen in 60 hours in Milford Sound, 600mm of that fell in the 24 hours to 7am today.
The flooding and heavy rain has led to the closure of most roads in Southland and some in Otago.
The Transport Agency has issued warnings to drivers in Westland to slow down for surface flooding and be ready for road closures.
More than 40 tourists trapped in lodges at Milford Sound were to be rescued by boat today.
A state of emergency was declared in the area yesterday afternoon as flooding and slips trapped tourists on tracks, roads and at Martins Bay and Big Bay, and closed State Highway 94, the only road into Milford Sound.
There are 125 people across three remote lodges owned by private company Ultimate Hikes.
Company spokesperson Shaun Liddy said they are looking to bring 44 tourists out to Te Anau by boat.
He said 81 will be left to stay another night.
Earlier today helicopters rescued 31 tourists out from the damaged Howden Hut. Eight helicopters ferried people from there to Te Anau, Glenorchy and Queenstown.
There are 195 people still stuck in Milford town and will stay there until the weather clears tomorrow when they can be transported out properly.
South Island roads cut off
Parts of the South are becoming isolated as heavy rain closes more roads this afternoon, including State Highway 1 in both directions from Gore.
SH1 except for a small section in Gore township is closed from Mataura to Clinton and SH6 is closed from Lumsden to Kingston. SH8 is closed between Roxburgh and Lake Roxburgh village, and SH94 (the Milford Road) is closed.
Several vehicles were this afternoon trapped by slips on SH6 north of Kingston, at the base of Lake Wakatipu near Queenstown.
The NZ Transport Agency and police were on site after landslides blocked the road.
And a carload of people had to be rescued from the top of their vehicle after getting into trouble on a flooded road this afternoon.
A Fire and Emergency New Zealand spokeswoman said they received a call at 12.50pm that some people had driven down Greenvale Rd where it was flooded, near Kelso.
They were standing on top of the car and had to be walked out by emergency services.
Dozens of roads are closed in South Otago and the Clutha District Council announced this afternoon that the Owaka Highway will close at 5.30pm due the expected levels of the Clutha River.
"Owing to the rain that has been falling steadily, Clutha District Council has received information that the Clutha River at Balclutha is expected to rise to 2200 cumecs between 6-11 pm tonight before climbing to 2500 cumecs by 4.00am tomorrow morning.
"River levels this high will make the Owaka Highway outside Balclutha impassable."
Welfare Centres are being opened by council at 5.30pm at the Cross Recreation Centre in Glasgow St, Balclutha and at the Owaka Community Centre, Ovenden St, Owaka.
"If you are travelling on the Owaka Highway and cannot get to your destination, feel free to call into one of the Welfare Centres for a cuppa. We are also trying to provide basic sleeping facilities."
Further west, State Highway 94 is closed and is expected to remain so for some time, isolating the township of Milford Sound.
In an update this evening the NZTA said SH94 would remain closed until at least next week because of damage from torrential rain and ongoing moving slips.
Evacuations in Gore
Flooding has forced the evacuation of about 50 people from a street in Gore today as heavy rain continues to batter the South.
Police and Gore District Council staff this afternoon evacuated about 15 homes and businesses in Ontario St, near the Mataura River, as floodwaters continued to rise.
A further 280 households, around 760 people, in East Gore were told to prepare for evacuation this evening.
The evacuations came on a day when a state of emergency was declared for Southland and many roads in the region were closed.
The council advised this evening it had activated a welfare centre in the town.
Council deputy chief executive Dr Ian Davidson-Watts said anyone stranded in Gore or forced out of their homes should go to the Calvin Church, in Robertson St.
"The Gore Visitor Centre has been inundated with requests for accommodation," he said.
About 50 people, adults and children, had been placed in commercial and private accommodation, he said.
Earlier, several schools closed for the day to ensure pupils could get home.
Dr Ian Davidson-Watts said there was a community response team at the Mataura service centre, working at keeping an eye on the flood protection and dealing with any issues in the town.
The ouvea premix - a fertiliser premix produced from toxic aluminium dross materials and stored at the Mataura paper mill - was one of the first considerations for the Council.
The owners were contacted earlier today and advised to put their flood protection defences in place, which has happened.
Emergency Management Southland is reassessing the situation to make sure it's capable of providing the maximum amount of protection and supplying additional sandbagging.
Council staff and contractors have been checking roads and clearing drains / culverts throughout the day.
"We also sent a team of staff to talk to people in Gore's worst affect streets to make sure they were okay.
"People were generally very positive and appreciated the call."
More rain on the way
A state of emergency was declared for Fiordland by Southland Mayor Gary Tong about 2pm yesterday to allow for a co-ordinated response to the flooding, caused by a combination of high tides and heavy rain.
Parts of Fiordland received 550mm of rain in 24 hours, the MetService says.
"In 24 hours Milford Sound recorded approximately as much rain as Christchurch gets in an entire year," MetService meteorologist Lewis Ferris said.
MetService is forecasting widespread heavy rain to continue affecting the South Island throughout today and tonight.
It earlier lifted its warning for Fiordland, saying heavy rain was easing in the area.
However a red alert level heavy rain warning is in place for Westland south of Hokitika until 10pm tonight.
MetService expects a further 60 to 90mm of rain to fall on the ranges on top of what has already fallen, and 30 to 50mm near the coast.
It said the rain would cause dangerous river conditions and significant flooding. Slips and floodwaters were likely to make some roads impassable and possibly isolate communities.
And an orange level heavy rain warning remains for Clutha and Southland until 9pm tonight, and around Dunedin, the headwaters of Otago and Canterbury lakes and rivers, the Southern Lakes and Central Otago until 11pm tonight.
People are advised to keep up to date with the latest forecasts.
-with RNZ and ODT