Off-duty firefighters have been called back to work in Canterbury to fight blazes sparked by the wild weather and more than 30,000 properties are without power.
Christchurch police are warning people not to travel at all around Canterbury because so much debris is flying around and weather and road conditions are so bad.
Electricity lines crews are unable to work because conditions are too dangerous and Christchurch Airport has closed.
The spate of fires stretches from North Canterbury to Timaru, started by trees falling on lines, as well as lines arcing. Severe electrical storms are also hitting much of the region.
A Fire Service spokesperson says all available engines and firefighters are working.
About 10pm nine fire engines were at West Melton, outside Christchurch, where flames that started in trees spread to a shed and were threatening a house.
At Leeston, a haybarn caught alight and there was a fire at the showgrounds there.
Flames that damaged a cow shed on a farm in nearby Southbridge were threatening a house; a silage pit was also alight.
The Fire Service warned of evacuations on Strangers Road in Ashburton, where flames threatened properties.
North of Ashburton, a fire was burning at a wood merchant on Lauriston Barrhill Road, in Lauriston.
A family at nearby Rakaia has lost a shelter belt of large pines and says it is the worst storm in the 32 years they have lived there.
Widespread power cuts
Lines company Orion says 28,257 customers don't have power. It says the Selwyn district west of Christchurch has been one of the worst affected areas but there are now outages in the city as well.
Another lines company, Mainpower, says at least 2,000 of its customers in North Canterbury will spend the night with no power and it expected Kaikoura to lose electricity overnight too.
Alpine Energy says about 1,000 of its customers around Waimate, Geraldine and Fairlie in South Canterbury will not have power overnight.
Chief executive Andrew Tombs says the winds are so strong and dangerous workers trying to repair the faults were stood down.
"To be snapping poles and even down in the Waimate region where we believe a pivot irrigation scheme was tumbled by the wind into our poles you've got to be getting up 150 kilometres an hour, perhaps in gusts even higher than that."
Aurora Energy says electricity supply was briefly cut to almost 1,700 properties in Arrowtown, Dalefield and Coronet Peak after a lightning strike earlier in the day. It said later in the day a small number of homes were still without power in Mosgiel, south of Dunedin.
Network Waitaki said earlier in the evening about 100 customers, including in Oamaru, remained without power.
Police are urging motorists to take extreme care on Canterbury roads and say drivers of high-sided vehicles and campervans, as well as motorcyclists, should consider delaying their travels.
Two trucks were blown over north of Dunedin on Tuesday afternoon. One driver was injured
Flights in and out of Dunedin Airport halted for some hours and flood warnings have been issued for Southland and Canterbury.
An Oamaru resident says the winds that hit the North Otago town are the worst he's experienced in a long time.
John Rapson says trees fell throughout the town, a power pole fell onto a building and a couple of trucks overturned on the outskirts.
Mr Rapson says he helped to secure an airship at the local Steampunk museum that was damaged by the storm.
Flights were cancelled or diverted at Dunedin Airport on Tuesday afternoon, with chief executive John McCall saying winds across the runways were too strong. Airlines resumed flights during the evening.
River flood warnings
Canterbury Regional Council has issued flood warnings for the Rakaia, Waimakariri, Hurunui and Waiau rivers.
MetService says 300mm to 400mm of rain is expected about the Westland ranges and the main divide in the next couple of days.
The Southland Regional Council has activated its flood warning as headwaters of major rivers rose rapidly after a day of heavy rainfall.
MetService is forecasting severe gales for Nelson and inland parts of Marlborough on Wednesday, with gusts of 90 to 100 kilometres an hour in the lower North Island, with winds gusting up to 140 kilometres an hour in Wellington.