Snow is expected to fall to very low levels in the south of the country with potentially damaging gales, torrential rain and snow lashing the country from Gisborne south.
Weatherwatch.co.nz is forecasting snow to fall down to sea level across Southland and Otago. Virtually nowhere in the South Island will escape a wintry white-out.
Travel across the country is expected to be disrupted and farmers are being advised to move livestock ahead of the wintry blast.
Coastal regions are being put on alert with possible flooding from strong onshore winds, high waves and heavy rain colliding in the storm. Sailings across Cook Strait could be in jeopardy with Niwa predicting waves of up to 4m by Thursday.
Snow is expected to fall for two straight days across the South Island - in some areas down to 100m in southernmost regions and down to 200m in Canterbury - followed by a bitterly cold southerly wind.
Yesterday a swathe of road snowfall warnings for major alpine passes and Dunedin's northern highway have been issued for coming days.
Projections show some alpine areas will get up to 1m of snow.
Tomorrow the weather will continue to worsen as it tracks north with severe gales, heavy rain and snow set to strike the centre of the country.
Gales are expected to batter Taranaki to Gisborne south and heavy rain is expected to fall across the lower half of the North Island.
Snow is expected to bring disruption to central and eastern areas and forecasters predict it will fall down to 600m across Wairarapa, Hawke's Bay and east of Taupo.
Weatherwatch.co.nz says the Wellington region could be hit by snow flurries down to 500m by dawn on Wednesday.
The weather is not expected to let up until Friday when it moves away from the North Island.
Motorists considering driving over mountain passes in winter were advised to take chains in case of snow and to check road conditions and the weather forecast before setting out.
