Christchurch shivered through its coldest day on record yesterday.

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The National Institute of Water amd Atmospheric Research says the paltry maximum temperature of 0.4 degrees Celsius at Christchurch Airport in the official 24-hour period from 9am yesterday to 9am today is the lowest in more than 130 years of record-keeping.

The previous lowest recorded daily maximum temperature in the city was 1.2C measured in the Christchurch Botanic Gardens on July 22, 1918.

Until yesterday, the coldest day maximum at the airport was 1.7C on August 28, 1992, during that year's big snow.

Commuters are urged to take extra care driving home tonight as snow melt risks turning to ice.

Seven minor crashes have been reported to police this afternoon in Canterbury, bringing the total of snow-related crashes today to 15. No injuries had been reported.

But Senior Sergeant Steve King, of the Canterbury Highway Patrol, said the risk was not yet over.

"There is still ice on many roads, and if melting snow refreezes then drivers may face similar hazards overnight and in the morning. Rural locations and shaded areas are particularly at risk."

Police were advising people to assess local conditions and avoid non-essential travel if the roads were icy, King said.

Those who did need to drive were advised to drive slowly, extend following distances, be patient and allow extra time for their trip.

Buses will stop at 6pm.

St John regional operations manager Chris Haines said ambulance crews in Canterbury, in particular in Christchurch, had been "very busy".

They had attended 20 incidents of people falling Christchurch, one in Rangiora and one in Tinwald since 6.30am.

Of the 20, 14 were taken by ambulance to Christchurch Hospital's emergency department.

Ambulances had been fitted with chains as required.

100 homes face another cold night

Most of the power has been restored in Christchurch and central Canterbury

Orion has announced that fewer than 300 customers were still without electricity in its network in Christchurch and central Canterbury.

Most of the affected customers were in the rural area west of Christchurch, including parts of Weedons, Hororata, Kimberley and Castle Hill.

"We know how difficult it is to be without power in these conditions, and we're working as quickly as we can to get power back to everyone," said Orion chief executive Rob Jamieson.

"Access difficulties are hampering efforts, especially in the Castle Hill area. In other places damage from trees falling into lines has been significant, which means repairs can take a long time."

Up to 100 homes in North Canterbury may face another cold night without power, Mainpower engineering manager Peter Hurford has confirmed.

There were currently about 200 homes without power in the area, but Hurford was hopeful power could be restored to about half of those properties before nightfall.

"We are getting through it as quickly as we can but there are some access problems and some problems on inidvidual properties. Unfortunately, there will probably be about 100 homes without power for a second night," he said.

Meanwhile, power in Kaikoura was back up and running and Hurford was confident it would now stay on for good.

"It's pretty solid now. We have a second line up so if one fails we can switch over."

About 2000 Kaikoura homes had lost power about 11am.

Ice risk for roads

Christchurch City Council has been working today to clear hill roads of snow and spread grit on icy road across the city.

Road conditions were improving as ice thaws, however freezing conditions were expected again tonight. Motorists were advised to take extreme caution on the roads while travelling around the city.

The status of Port Hills and Banks Peninsula roads remained unchanged from earlier reports.

Kerbside collection

Wednesday's kerbside collection areas, on the flat, would be completed by the end of today.

For residents on a Thursday collection, whose bins have not been collected today, the council has asked the bins to be left at kerbside.

If bins have not been collected by Saturday afternoon residents should call the council on 941 8999 or 0800 800 169.

Any uncollected bins should be placed back out for collection by 6am on Monday morning.

Seven streets in Lyttelton were not able to be collected today due to hazardous icy conditions. These would be collected tomorrow and Monday. Residents are asked to leave their bins out at the kerbside for collection.

Residents living on lanes in hill areas, whose wheelie bins are normally collected on a Wednesday, Thursday, or Friday should leave their bins out for collection. Collection was expected to be completed by Friday evening.

Recreation and sports centres

All Council recreation and sports centres would open at 9am tomorrow morning. This was to help to reduce the risk of ice creating a hazard for customers in the facilities' car parks.

Meanwhile, Lincoln University said students who were meant to sit exams today will receive an aegrotat consideration.

Essential services on the campus, including catering, accommodation, library and recreation centre were operating.

Tomorrow's exams are expected to be held. An update is expected about 5pm.

Flights disrupted

Some Air New Zealand flight operations resumed at Christchurch Airport this afternoon as conditions begin to improve.

However, the weather saw a large number of flights disrupted across the country.

Customers will be booked onto the next available service as flights are able to operate again.

Air New Zealand customers are advised to check the Air New Zealand website for arrivals and departures information, which will be updated throughout the day.