Power is back on for around 5000 Christchurch homes, after nearly 10,000 were cut out after fierce weather lashed the region last night.
Some 4800 are still without power, but lines company Orion said it was still working as quickly as it could to get it restored.
Emergency services have been inundated with calls about felled trees, fences, and power lines.
"We've got fierce winds and weather, and there's trees down everywhere," said Police spokesman Paul Visser.
"Probably the worst hit is North Canterbury."
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Lines company Orion said power was cut to 9800 customers early this morning because of the strong winds, with most outages southwest of Christchurch.
Crews were working to get power restored by midday.
Some of the felled lines sparked scrub fires which destroyed a farm shed and forced two houses to be evacuated, said a fire spokesman.
Around 2am a wind gust blew over power lines which set trees and shrubbery on fire, and the blaze spread about three kilometres down Powells Road, Springston.
He said a few units were still at the scene to make sure the fire did not spark up again.
High winds have also caused chaos in the Kaikoura area. A truck and trailer unit was blown over on SH 1 just north of Kaikoura.
The truck driver received minor injuries. Police have advised that trees have blown over so extreme care is needed if travelling on SH 1 and other roads in the area.
Metservice said the winds in Canterbury had eased for the moment, but were expected to strengthen again this evening.
From Saturday evening until late Sunday evening, severe gales were still possible in some places with gusts of 130km/hr.
Wild weather sweeping the South Island was part of an active trough moving up the country.
Heavy rain was expected for Westland, Fiordland and near the Main Divide, with northwest gales for eastern areas of the South Island.
These severe gales had the strength to topple trees and power lines, damage unsecured structures, and make driving conditions hazardous, said Metservice.
The northwest flow over the South Island was expected to remain until Sunday.
Metservice expected significant spillover for the headwaters of the Otago and Canterbury lakes and rivers, and advised heavy rain could cause flooding and slips.
"Rivers and streams may rise rapidly, including those in eastern Otago and Canterbury, where there may be little rain but are also likely to respond to heavy rain falling in the headwaters," Metservice said.
Severe gales were expected for Wellington and Wairarapa, with gusts reaching 130km/h possible in some places.
Metservice's Daniel Corbett said the system would weaken as it moved up the country to the north of the North Island.
- Fairfax Media