Gales and heavy rain lashed Wellington on Tuesday night, with electricity cut to some homes.
The MetService said gusts of up to 120km/h were expected in Wellington, as well as in Westland, Buller, parts of Nelson and the Marlborough Sounds.
About 250 homes are without power in Titahi Bay after a tree brought down a power line at 6.30pm on Tuesday.
A power cut has also affected 28 homes in Plimmerton.
Wellington Electricity says strong gales made it difficult for repair staff, but power was restored before midnight.
Earlier on Tuesday, a combination of heavy rain and blocked drains flooded six homes and closed part of a major road in west Auckland.
Some roads in the South Island are closed or restricted due to snow or flooding.