Two people have been injured as heavy rain, wild winds and driving snow are blasting up the country.
The two people were injured when a tree fell on their car near Tai Tapu. They will be transferred to Christchurch Hospital with moderate injuries, St John says.
There's also damage in Dunedin and Christchurch, with trees down and powerlines down over Dunedin's High St.
Police have closed the road while contractors make the lines safe.
More than 2500 Orion electricity customers in Christchurch are without power.
Several trees have been blown down as gale force winds of up to 160km/h hit the area.
Meanwhile, Aurora Energy says customers in Otago should be ready for the possibility of power outages.
Around 380 homes have been reconnected, but there are still a number of isolated outages in the area.
Tree down in St Albans, Christchurch
The gusting winds have also lifted roofing iron in Fernside near Rangiora. Emergency services say it's too dangerous to secure. They are bracing for a busy night.
The late southerly snap interrupted the early arrival of spring weather.
Everyone crossing the Crown Range had to carry chains. Passengers were stopping to take in the September snow.
The bitter conditions and cold winds are a huge concern for farmers with newborn lambs in central Otago. It's more bad news for them though, as strong wind warnings are forecast for coastal areas across the South Island.
The fierce southlerly blast quickly moved north late afternoon, turning blue skies to cloud and proving there's still a bit of life left in the winter season yet.
Clouds are seen by Christchurch Airport as they make their way up the country (Lisa Clark)
Wind gusts of 150km/h are expected during Wednesday and early Thursday for coastal eastern Southland, Clutha, Dunedin and the Otago and Banks Peninsulas, and from late Wednesday to late Thursday for the Kaikoura Peninsula and Wellington. Winds could cause damage and make driving hazardous.
Mt Hutt ski field near Christchurch is closed due to strong winds.
As it moves north huge swells are expected, which could cause trouble for the Interislander ferry, which is warning passengers of sizable swells and saying if no one feels comfortable sailing through the conditions it will let them change for free.
Interislander is also refusing to take any bookings for sailings over the next three days.
Cook Strait ferry sailings are cancelled when waves top six metres. Bookings will reopen once swells have calmed.
Otago's Crown Ranges covered in snow (Grant Findlay / Newshub.)
While snow is unlikely to reach central Christchurch, it is expected to fall to low-levels - 100 to 200 metres above sea level - over the nearby Port Hills and Banks Peninsula where strong gusts are also forecast.
A heavy snow warning is in place for Taihape and Taupo where up to 30cm of the white stuff is expected above 500 metres on Thursday.
The system is expected to hit Wellington about 7pm on Wednesday bringing bitterly cold winds, with temperatures set to drop to as low as 6degC in some areas on Thursday.
The good news is that conditions are expected to ease across the country by Friday and a warmer, drier weekend is forecast.
Newshub. / NZN