Central New Zealand has been warned to brace for heavy rain, snow and severe southerly gales as a cold blast continues to sweep through the country.
MetService says the "significant weather event" is expected to cause widespread disruption to transport, especially about higher roads and lead to localised flooding and slips.
The wind strength - with predicted gusts of 140km/h in Wellington on Wednesday night and Thursday morning - could cause damage to trees, powerlines and unsecured roofs.
The heaviest snow is expected to be in north Canterbury and Kaikoura District above 400 metres and the central North Island high country above 600 metres, with over 20 cm likely through to Thursday afternoon.
The lower North Island, especially Wairarapa, Wellington, Kapiti and higher parts of Manawatu will cop heavy rainfall.
Southerly gales will continue to affect central New Zealand until Friday, with severe gales about the Marlborough Sounds, Wellington, Kapiti and Taranaki.
The weather has disrupted domestic flights, while all Cook Strait ferry sailings have been cancelled until Friday afternoon.
After at least a dozen crashes across Otago and Southland since Wednesday morning, the NZ Transport Agency has asked anyone who can stay home to do so.
"In many places snow is lying on top of ice making driving extremely dangerous," journey manager Lee Wright said.
Snow has closed several stretches of highway in the South Island, including the only road into Kaikoura.
SOUTH ISLAND HIGHWAYS CLOSED BY SNOW
* SH70 Peketa to Waiau
* SH73 Springfield to Arthurs Pass
* SH7 Springs Junction to Hanmer Springs
* SH87 Middlemarch to Outram
* SH85 Kyeburn to Palmerston
* SH93 Mataura to Clinton.