A subtropical low bearing down on the country is bringing severe gales, heavy rain and big seas.
The harsh conditions are forecast to slam into the upper North Island today, with the northeast corner of the South Island also likely to be in the firing line as the low moves south.
"After the heavy thundery downpours that moved across many parts of New Zealand during the weekend, Monday provided a brief respite from the weather. However, the outlook for the rest of the week is bleak," MetService said.
Intense rain and severe easterly gales would spread down across the North Island, reaching the top of the South Island from late today.
Rainfall could be heavy in eastern Marlborough. Southeasterlies could also reach severe gale strength for a time on Wednesday about the Marlborough Sounds, in Gisborne and North Island areas west of the main ranges.
Mr Corbett said the intense low would gradually weaken on Thursday. Disturbed westerlies were likely to take its place by the end of the week.
- The Marlborough Express