Minister for Emergency Management and Recovery Mark Mitchell said the measure was "a precautionary step due to concern about the potential impacts from power outages" from yesterday's storm.
“The state of local emergency will ensure local Civil Defence have access to the emergency powers they need to respond and support emergency services during this event," he said in a statement.
He made the declaration because Southland mayors has yet to be sworn in following the recent local elections.
“With further bad weather expected for some parts of the country early next week, people should stay up to date with the latest weather information from MetService,” Mr Mitchell said.
The previous state of local emergency declared for Canterbury remained in force, he said
Several Southland towns have no drinking water and thousands across the South face being without electricity "well into the weekend".
Tuatapere, Ohai and Mossburn are all without drinking water due to water treatment plants being down.
A water truck is stationed in the main street of Tuatapere opposite the Four Square. Water from it must be boiled before consumption.
"If you have no power use a gas stove or any camping equipment suitable for boiling water," the council said.
Another water truck will be sent to Mossburn soon, Southland District Council said around 7.30am.
Southland Mayor Rob Scott urged people to conserve water.
"We do have generators across some of our plants, but there's a shortage of generators around the traps at the moment," he said.
"We're doing what we can and we're actively monitoring, but it's just important that people to conserve water where they can."
Powernet said tens of thousands of properties were affected in Otago and Southland.
"Our crews are focused on making damaged infrastructure like downed lines and poles safe, then restoring electricity to lifeline utilities like water supplies and water treatment plants," it said.
"It is possible that some customers may be without power well into the weekend, or longer, as the extent of the damage becomes clear."
Power cuts were also impacting drinking and wastewater plants in Southland - which was a particular problem for the townships of Tuatapere, Ohai, Nightcaps and Otautau.
Southland bore by far the main brunt of yesterday’s storm system.
A massive cleanup effort will kick in today, but residents have been warned it could take days for some power — which remained out in large parts of the region last night — to be restored.
There have been reports of widespread damage across the region to homes, buildings and roads.
Forty percent (228) of Fire and Emergency Services New Zealand’s 587 callouts in New Zealand yesterday were in Southland.
The bulk of those (155) were in Invercargill, which was thrashed by winds of up to 150kmh and driving rain for several hours from 10am.
Trees torn from the ground and tossed back down blocked roads, brought down power lines and fences, and landed on vehicles.
Emergency Management Southland group controller Lucy Hicks said the situation was serious.
PowerNet was dealing with the live powerlines first and would be restoring power as swiftly as they could once any damage had been assessed.
Restoring power to critical services was prioritised last night.
"It is expected the recovery from this weather event will go on longer than the incident itself, with power, water and communication outages expected to continue across the next couple of days,” she said.
No serious injuries were reported but a coffee van owner had a close call when a large tree fell on her bonnet as she was driving.
The Shot South owner Justine Abbott said she was in North Rd when the tree "came out of nowhere".
Ms Abbott had just decided to head home in the worsening weather conditions.
"I started slowing down, and it went ‘boom’."
Southland District Mayor Rob Scott painted a grim picture of the situation in the district, saying water and wastewater schemes were also under pressure while on emergency generators.
He asked residents to conserve water due to the treatment plants losing power.
Meanwhile, dairy farmers affected by power outages scrambled to hire generators to continue milking operations.
In Edendale, 30 minutes north of Invercargill, a significant portion of the roof of Fonterra’s new $150million under-construction UHT plant was blown off.
A Mataura resident said lines of trees along the sides of the road between Gore and Edendale were down, as were farm shelterbelts and fence lines, and a trampoline had blown on to his neighbour’s roof.
Power and water were out in the town yesterday afternoon, he said.
The man, in his early 50s, had lived in Mataura his whole life and had never seen wind like it.
A Gore District Council spokesman said last night severe winds caused significant disruption to services across the district and damaged infrastructure.
People were asked to be careful because of power lines brought down by the winds causing hazards on the roads.
All Gore district residents were asked to limit water use after a burst water pipe and fallen tree cut supply to Martin St.
Repairs were expected to be completed today.
Department of Conservation Whakatipu-wai-Maori operations manager David Butt said severe weather had created the potential for flooding, slips and track damage across Fiordland, Southland and Otago.
Rangers had not yet been able to assess damage, but were advising people heading to holiday destinations for Labour Weekend to be cautious and get up-to-date weather reports.
— Allied Media and LDR
■ LDR is local body journalism co-funded by RNZ and NZ On Air.
