Some inland areas of New Zealand South Island's Otago and Canterbury have received on Thursday their largest snowfalls in decades in a winter storm that has cut power to thousands of people, and some coastal areas are also flooded.

Christchurch and Dunedin missed out on the anticipated snow storm, but inland areas bore the brunt of the polar blast. Provincial towns and settlements have been hit hard, with 36 schools from Canterbury to Southland having to close and thousands were without power.

The MetService has been warning of the storm's power all week, but the amount of snow and rain dumped since Wednesday has surprised many people. The forecaster warns the worst is yet to come, with warnings of heavy snow for Canterbury and Kaikoura above 300 metres on Thursday night and Friday.

Some 3,500 households in Canterbury and Southland had no electricity when they woke up due to heavy snow on Thursday morning.

Heavy rain in Dunedin has caused two big slips. About 30 metres of hillside fell away in heavy rain on Wednesday night, crashing onto a house on Blanket Bay Road. Police had to free a woman living at the property.

The Otago Regional Council says there has been 75 millimeters of rain in 24 hours, flooding paddocks and low-lying land.

Porters Pass to Arthur's Pass, Lewis Pass, Lindis Pass, Burkes Pass and Danseys Pass along with eight state highways are closed to due to snow on Thursday.

New Zealand Transport Agency advised motorists to avoid non- essential travel as conditions are forecast to get worse over by Friday.

The agency is also warning drivers to watch for surface flooding on State Highway 1 between East Taieri and Milton.

Southerlies are expected to rise to severe gales in the North Island on Thursday night, with damaging gusts of up to 130km/h in exposed places.

Severe gales are forecast for Wellington, including the Kapiti Coast, as well as Auckland and Northland.

All Interislander ferry services will be suspended until Friday afternoon due to predicted high waves of up to eight metres. The last sailing is a cargo service at 6.30 p.m. on Thursday.

Strong winds in Wellington have forced the cancellation of numerous flights in and out of the city this evening.

An Air New Zealand spokesperson said that all regional Link services have been canceled on Thursday night and jet services are suspended and being monitored on a flight by flight basis.

Winds at the airport have been strengthening through out Thursday afternoon with gusts up to 120 kph.